Remove six

Replace the following items with Python 3 style code.

- six.moves
- six.PY2
- six.PY3
- six.string_types
- six.text_type

Change-Id: I1656b976864c8f2343e658a4abf432d30c151d0b

26 files changed, 94 insertions, 322 deletions

diff --git a/cliff/_argparse.py b/cliff/_argparse.py
index 07a5a77..c03d709 100644
--- a/cliff/_argparse.py
+++ b/cliff/_argparse.py
@@ -13,7 +13,6 @@
 """Overrides of standard argparse behavior."""
 
 import argparse
-import sys
 import warnings
 
 
@@ -44,16 +43,7 @@ class _ArgumentContainerMixIn(object):
 
 class ArgumentParser(_ArgumentContainerMixIn, argparse.ArgumentParser):
 
-    if sys.version_info < (3, 5):
-        def __init__(self, *args, **kwargs):
-            self.allow_abbrev = kwargs.pop("allow_abbrev", True)
-            super(ArgumentParser, self).__init__(*args, **kwargs)
-
-        def _get_option_tuples(self, option_string):
-            if self.allow_abbrev:
-                return super(ArgumentParser, self)._get_option_tuples(
-                    option_string)
-            return ()
+    pass
 
 
 def _handle_conflict_ignore(container, option_string_actions,
diff --git a/cliff/app.py b/cliff/app.py
index 88b39d2..603778d 100644
--- a/cliff/app.py
+++ b/cliff/app.py
@@ -13,12 +13,10 @@
 """Application base class.
 """
 
-import codecs
 import locale
 import logging
 import logging.handlers
 import os
-import six
 import sys
 
 import cmd2
@@ -118,18 +116,6 @@ class App(object):
         # has not already already wrapped sys.stdin, sys.stdout and
         # sys.stderr as this is a common recommendation.
 
-        if six.PY2:
-            encoding = locale.getpreferredencoding()
-            if encoding:
-                if not (stdin or isinstance(sys.stdin, codecs.StreamReader)):
-                    stdin = codecs.getreader(encoding)(sys.stdin)
-
-                if not (stdout or isinstance(sys.stdout, codecs.StreamWriter)):
-                    stdout = utils.getwriter(encoding)(sys.stdout)
-
-                if not (stderr or isinstance(sys.stderr, codecs.StreamWriter)):
-                    stderr = utils.getwriter(encoding)(sys.stderr)
-
         self.stdin = stdin or sys.stdin
         self.stdout = stdout or sys.stdout
         self.stderr = stderr or sys.stderr
diff --git a/cliff/columns.py b/cliff/columns.py
index abf1c4f..c2b5fe1 100644
--- a/cliff/columns.py
+++ b/cliff/columns.py
@@ -15,11 +15,8 @@
 
 import abc
 
-import six
 
-
-@six.add_metaclass(abc.ABCMeta)
-class FormattableColumn(object):
+class FormattableColumn(object, metaclass=abc.ABCMeta):
 
     def __init__(self, value):
         self._value = value
diff --git a/cliff/command.py b/cliff/command.py
index 663b467..f8d0501 100644
--- a/cliff/command.py
+++ b/cliff/command.py
@@ -13,7 +13,6 @@
 import abc
 import inspect
 
-import six
 from stevedore import extension
 
 from cliff import _argparse
@@ -60,8 +59,7 @@ def _get_distribution_for_module(module):
     return dist_name
 
 
-@six.add_metaclass(abc.ABCMeta)
-class Command(object):
+class Command(object, metaclass=abc.ABCMeta):
     """Base class for command plugins.
 
     When the command is instantiated, it loads extensions from a
diff --git a/cliff/complete.py b/cliff/complete.py
index 472a14e..06f38be 100644
--- a/cliff/complete.py
+++ b/cliff/complete.py
@@ -15,7 +15,6 @@
 
 import logging
 
-import six
 import stevedore
 
 from cliff import command
@@ -40,7 +39,7 @@ class CompleteDictionary:
             # For example, {'cmd': 'action'}, and we add the command
             # 'cmd_other'. We want the result to be
             # {'cmd': 'action other', 'cmd_other': 'sub_action'}
-            if isinstance(subdata, six.string_types):
+            if isinstance(subdata, str):
                 subdata += ' ' + last_cmd
                 dicto[subcmd] = subdata
                 last_cmd = subcmd + '_' + last_cmd
@@ -57,7 +56,7 @@ class CompleteDictionary:
         for cmd in keys:
             name = path + "_" + cmd if path else cmd
             value = dictionary[cmd]
-            if isinstance(value, six.string_types):
+            if isinstance(value, str):
                 ray.append((name, value))
             else:
                 cmdlist = ' '.join(sorted(value.keys()))
diff --git a/cliff/display.py b/cliff/display.py
index 73d68a8..5ea0713 100644
--- a/cliff/display.py
+++ b/cliff/display.py
@@ -15,14 +15,12 @@
 import abc
 from itertools import compress
 
-import six
 import stevedore
 
 from . import command
 
 
-@six.add_metaclass(abc.ABCMeta)
-class DisplayCommandBase(command.Command):
+class DisplayCommandBase(command.Command, metaclass=abc.ABCMeta):
     """Command base class for displaying data about a single object.
     """
 
diff --git a/cliff/formatters/base.py b/cliff/formatters/base.py
index 920cb32..ca65928 100644
--- a/cliff/formatters/base.py
+++ b/cliff/formatters/base.py
@@ -15,11 +15,8 @@
 
 import abc
 
-import six
 
-
-@six.add_metaclass(abc.ABCMeta)
-class Formatter(object):
+class Formatter(object, metaclass=abc.ABCMeta):
 
     @abc.abstractmethod
     def add_argument_group(self, parser):
@@ -29,8 +26,7 @@ class Formatter(object):
         """
 
 
-@six.add_metaclass(abc.ABCMeta)
-class ListFormatter(Formatter):
+class ListFormatter(Formatter, metaclass=abc.ABCMeta):
     """Base class for formatters that know how to deal with multiple objects.
     """
 
@@ -53,8 +49,7 @@ class ListFormatter(Formatter):
         """
 
 
-@six.add_metaclass(abc.ABCMeta)
-class SingleFormatter(Formatter):
+class SingleFormatter(Formatter, metaclass=abc.ABCMeta):
     """Base class for formatters that work with single objects.
     """
 
diff --git a/cliff/formatters/commaseparated.py b/cliff/formatters/commaseparated.py
index c3511b4..7536817 100644
--- a/cliff/formatters/commaseparated.py
+++ b/cliff/formatters/commaseparated.py
@@ -13,19 +13,12 @@
 """Output formatters using csv format.
 """
 
+import csv
 import os
-import sys
 
 from .base import ListFormatter
 from cliff import columns
 
-import six
-
-if sys.version_info[0] == 3:
-    import csv
-else:
-    import unicodecsv as csv
-
 
 class CSVLister(ListFormatter):
 
@@ -53,22 +46,11 @@ class CSVLister(ListFormatter):
             escapechar='\\',
         )
 
-        # In Py2 we replace the csv module with unicodecsv because the
-        # Py2 csv module cannot handle unicode. unicodecsv encodes
-        # unicode objects based on the value of it's encoding keyword
-        # with the result unicodecsv emits encoded bytes in a str
-        # object. The utils.getwriter assures no attempt is made to
-        # re-encode the encoded bytes in the str object.
-
-        if six.PY2:
-            writer_kwargs['encoding'] = (getattr(stdout, 'encoding', None)
-                                         or 'utf-8')
-
         writer = csv.writer(stdout, **writer_kwargs)
         writer.writerow(column_names)
         for row in data:
             writer.writerow(
-                [(six.text_type(c.machine_readable())
+                [(str(c.machine_readable())
                   if isinstance(c, columns.FormattableColumn)
                   else c)
                  for c in row]
diff --git a/cliff/formatters/shell.py b/cliff/formatters/shell.py
index 6e7bae9..d02ebe0 100644
--- a/cliff/formatters/shell.py
+++ b/cliff/formatters/shell.py
@@ -17,7 +17,6 @@ from . import base
 from cliff import columns
 
 import argparse
-import six
 
 
 class ShellFormatter(base.SingleFormatter):
@@ -50,12 +49,12 @@ class ShellFormatter(base.SingleFormatter):
         desired_columns = parsed_args.variables
         for name, value in zip(variable_names, data):
             if name in desired_columns or not desired_columns:
-                value = (six.text_type(value.machine_readable())
+                value = (str(value.machine_readable())
                          if isinstance(value, columns.FormattableColumn)
                          else value)
-                if isinstance(value, six.string_types):
+                if isinstance(value, str):
                     value = value.replace('"', '\\"')
-                if isinstance(name, six.string_types):
+                if isinstance(name, str):
                     # Colons and dashes may appear as a resource property but
                     # are invalid to use in a shell, replace them with an
                     # underscore.
diff --git a/cliff/formatters/table.py b/cliff/formatters/table.py
index 22f7300..397777c 100644
--- a/cliff/formatters/table.py
+++ b/cliff/formatters/table.py
@@ -14,7 +14,6 @@
 """
 
 import prettytable
-import six
 import os
 
 from cliff import utils
@@ -27,7 +26,7 @@ def _format_row(row):
     for r in row:
         if isinstance(r, columns.FormattableColumn):
             r = r.human_readable()
-        if isinstance(r, six.string_types):
+        if isinstance(r, str):
             r = r.replace('\r\n', '\n').replace('\r', ' ')
         new_row.append(r)
     return new_row
diff --git a/cliff/formatters/value.py b/cliff/formatters/value.py
index 24125c0..d4e646a 100644
--- a/cliff/formatters/value.py
+++ b/cliff/formatters/value.py
@@ -13,8 +13,6 @@
 """Output formatters values only
 """
 
-import six
-
 from . import base
 from cliff import columns
 
@@ -28,15 +26,15 @@ class ValueFormatter(base.ListFormatter, base.SingleFormatter):
         for row in data:
             stdout.write(
                 ' '.join(
-                    six.text_type(c.machine_readable()
-                                  if isinstance(c, columns.FormattableColumn)
-                                  else c)
+                    str(c.machine_readable()
+                        if isinstance(c, columns.FormattableColumn)
+                        else c)
                     for c in row) + u'\n')
         return
 
     def emit_one(self, column_names, data, stdout, parsed_args):
         for value in data:
-            stdout.write('%s\n' % six.text_type(
+            stdout.write('%s\n' % str(
                 value.machine_readable()
                 if isinstance(value, columns.FormattableColumn)
                 else value)
diff --git a/cliff/hooks.py b/cliff/hooks.py
index 5dc9b29..44e0402 100644
--- a/cliff/hooks.py
+++ b/cliff/hooks.py
@@ -12,11 +12,8 @@
 
 import abc
 
-import six
 
-
-@six.add_metaclass(abc.ABCMeta)
-class CommandHook(object):
+class CommandHook(object, metaclass=abc.ABCMeta):
     """Base class for command hooks.
 
     :param app: Command instance being invoked
diff --git a/cliff/lister.py b/cliff/lister.py
index e0fab01..cfba233 100644
--- a/cliff/lister.py
+++ b/cliff/lister.py
@@ -14,13 +14,11 @@
 """
 import abc
 import operator
-import six
 
 from . import display
 
 
-@six.add_metaclass(abc.ABCMeta)
-class Lister(display.DisplayCommandBase):
+class Lister(display.DisplayCommandBase, metaclass=abc.ABCMeta):
     """Command base class for providing a list of data as output.
     """
 
diff --git a/cliff/show.py b/cliff/show.py
index dc6482a..6273c0e 100644
--- a/cliff/show.py
+++ b/cliff/show.py
@@ -14,13 +14,10 @@
 """
 import abc
 
-import six
-
 from . import display
 
 
-@six.add_metaclass(abc.ABCMeta)
-class ShowOne(display.DisplayCommandBase):
+class ShowOne(display.DisplayCommandBase, metaclass=abc.ABCMeta):
     """Command base class for displaying data about a single object.
     """
 
diff --git a/cliff/tests/test_app.py b/cliff/tests/test_app.py
index d31cd3d..41a28b7 100644
--- a/cliff/tests/test_app.py
+++ b/cliff/tests/test_app.py
@@ -14,14 +14,7 @@
 
 import argparse
 import codecs
-import locale
-try:
-    from StringIO import StringIO
-except ImportError:
-    from io import StringIO
-import sys
-
-import six
+import io
 from unittest import mock
 
 from cliff import app as application
@@ -30,6 +23,7 @@ from cliff import commandmanager
 from cliff.tests import base
 from cliff.tests import utils as test_utils
 from cliff import utils
+import sys
 
 
 def make_app(**kwargs):
@@ -395,7 +389,7 @@ class TestCommandLookup(base.TestBase):
             self.assertIn("['hell']", str(err))
 
     def test_list_matching_commands(self):
-        stdout = StringIO()
+        stdout = io.StringIO()
         app = application.App('testing', '1',
                               test_utils.TestCommandManager(
                                   test_utils.TEST_NAMESPACE),
@@ -473,86 +467,27 @@ class TestIO(base.TestBase):
         cmd_mgr = commandmanager.CommandManager('cliff.tests')
         io = mock.Mock()
 
-        if six.PY2:
-            stdin_save = sys.stdin
-            stdout_save = sys.stdout
-            stderr_save = sys.stderr
-            encoding = locale.getpreferredencoding() or 'utf-8'
-
-            app = application.App('no io streams', 1, cmd_mgr)
-            self.assertIsInstance(app.stdin, codecs.StreamReader)
-            self.assertIsInstance(app.stdout, codecs.StreamWriter)
-            self.assertIsInstance(app.stderr, codecs.StreamWriter)
-
-            app = application.App('with stdin io stream', 1, cmd_mgr, stdin=io)
-            self.assertIs(io, app.stdin)
-            self.assertIsInstance(app.stdout, codecs.StreamWriter)
-            self.assertIsInstance(app.stderr, codecs.StreamWriter)
-
-            app = application.App('with stdout io stream', 1, cmd_mgr,
-                                  stdout=io)
-            self.assertIsInstance(app.stdin, codecs.StreamReader)
-            self.assertIs(io, app.stdout)
-            self.assertIsInstance(app.stderr, codecs.StreamWriter)
-
-            app = application.App('with stderr io stream', 1, cmd_mgr,
-                                  stderr=io)
-            self.assertIsInstance(app.stdin, codecs.StreamReader)
-            self.assertIsInstance(app.stdout, codecs.StreamWriter)
-            self.assertIs(io, app.stderr)
-
-            try:
-                sys.stdin = codecs.getreader(encoding)(sys.stdin)
-                app = application.App(
-                    'with wrapped sys.stdin io stream', 1, cmd_mgr)
-                self.assertIs(sys.stdin, app.stdin)
-                self.assertIsInstance(app.stdout, codecs.StreamWriter)
-                self.assertIsInstance(app.stderr, codecs.StreamWriter)
-            finally:
-                sys.stdin = stdin_save
-
-            try:
-                sys.stdout = codecs.getwriter(encoding)(sys.stdout)
-                app = application.App('with wrapped stdout io stream', 1,
-                                      cmd_mgr)
-                self.assertIsInstance(app.stdin, codecs.StreamReader)
-                self.assertIs(sys.stdout, app.stdout)
-                self.assertIsInstance(app.stderr, codecs.StreamWriter)
-            finally:
-                sys.stdout = stdout_save
-
-            try:
-                sys.stderr = codecs.getwriter(encoding)(sys.stderr)
-                app = application.App('with wrapped stderr io stream', 1,
-                                      cmd_mgr)
-                self.assertIsInstance(app.stdin, codecs.StreamReader)
-                self.assertIsInstance(app.stdout, codecs.StreamWriter)
-                self.assertIs(sys.stderr, app.stderr)
-            finally:
-                sys.stderr = stderr_save
+        app = application.App('no io streams', 1, cmd_mgr)
+        self.assertIs(sys.stdin, app.stdin)
+        self.assertIs(sys.stdout, app.stdout)
+        self.assertIs(sys.stderr, app.stderr)
 
-        else:
-            app = application.App('no io streams', 1, cmd_mgr)
-            self.assertIs(sys.stdin, app.stdin)
-            self.assertIs(sys.stdout, app.stdout)
-            self.assertIs(sys.stderr, app.stderr)
-
-            app = application.App('with stdin io stream', 1, cmd_mgr, stdin=io)
-            self.assertIs(io, app.stdin)
-            self.assertIs(sys.stdout, app.stdout)
-            self.assertIs(sys.stderr, app.stderr)
-
-            app = application.App('with stdout io stream', 1, cmd_mgr,
-                                  stdout=io)
-            self.assertIs(sys.stdin, app.stdin)
-            self.assertIs(io, app.stdout)
-            self.assertIs(sys.stderr, app.stderr)
-
-            app = application.App('with stderr io stream', 1, cmd_mgr,
-                                  stderr=io)
-            self.assertIs(sys.stdin, app.stdin)
-            self.assertIs(sys.stdout, app.stdout)
-            self.assertIs(io, app.stderr)
+        app = application.App('with stdin io stream', 1, cmd_mgr, stdin=io)
+        self.assertIs(io, app.stdin)
+        self.assertIs(sys.stdout, app.stdout)
+        self.assertIs(sys.stderr, app.stderr)
+
+        app = application.App('with stdout io stream', 1, cmd_mgr,
+                              stdout=io)
+        self.assertIs(sys.stdin, app.stdin)
+        self.assertIs(io, app.stdout)
+        self.assertIs(sys.stderr, app.stderr)
+
+        app = application.App('with stderr io stream', 1, cmd_mgr,
+                              stderr=io)
+        self.assertIs(sys.stdin, app.stdin)
+        self.assertIs(sys.stdout, app.stdout)
+        self.assertIs(io, app.stderr)
 
     def test_writer_encoding(self):
         # The word "test" with the e replaced by
@@ -561,45 +496,12 @@ class TestIO(base.TestBase):
         text = u't\u00E9st'
         text_utf8 = text.encode('utf-8')
 
-        if six.PY2:
-            # In PY2 StreamWriter can't accept non-ASCII encoded characters
-            # because it must first promote the encoded byte stream to
-            # unicode in order to encode it in the desired encoding.
-            # Because the encoding of the byte stream is not known at this
-            # point the default-encoding of ASCII is utilized, but you can't
-            # decode a non-ASCII charcater to ASCII.
-            io = six.StringIO()
-            writer = codecs.getwriter('utf-8')(io)
-            self.assertRaises(UnicodeDecodeError,
-                              writer.write,
-                              text_utf8)
-
-            # In PY2 with our override of codecs.getwriter we do not
-            # attempt to encode bytes in a str object (only unicode
-            # objects) therefore the final output string should be the
-            # utf-8 encoded byte sequence
-            io = six.StringIO()
-            writer = utils.getwriter('utf-8')(io)
-            writer.write(text)
-            output = io.getvalue()
-            self.assertEqual(text_utf8, output)
-
-            io = six.StringIO()
-            writer = utils.getwriter('utf-8')(io)
-            writer.write(text_utf8)
-            output = io.getvalue()
-            self.assertEqual(text_utf8, output)
-        else:
-            # In PY3 you can't write encoded bytes to a text writer
-            # instead text functions require text.
-            io = six.StringIO()
-            writer = utils.getwriter('utf-8')(io)
-            self.assertRaises(TypeError,
-                              writer.write,
-                              text)
-
-            io = six.StringIO()
-            writer = utils.getwriter('utf-8')(io)
-            self.assertRaises(TypeError,
-                              writer.write,
-                              text_utf8)
+        # In PY3 you can't write encoded bytes to a text writer
+        # instead text functions require text.
+        out = io.StringIO()
+        writer = codecs.getwriter('utf-8')(out)
+        self.assertRaises(TypeError, writer.write, text)
+
+        out = io.StringIO()
+        writer = codecs.getwriter('utf-8')(out)
+        self.assertRaises(TypeError, writer.write, text_utf8)
diff --git a/cliff/tests/test_formatters_csv.py b/cliff/tests/test_formatters_csv.py
index 1767705..608137e 100644
--- a/cliff/tests/test_formatters_csv.py
+++ b/cliff/tests/test_formatters_csv.py
@@ -14,9 +14,8 @@
 #  under the License.
 
 import argparse
+import io
 import unittest
-
-import six
 from unittest import mock
 
 from cliff.formatters import commaseparated
@@ -32,7 +31,7 @@ class TestCSVFormatter(unittest.TestCase):
         d2 = ('D', 'E', 'F')
         data = [d1, d2]
         expected = 'a,b,c\nA,B,C\nD,E,F\n'
-        output = six.StringIO()
+        output = io.StringIO()
         parsed_args = mock.Mock()
         parsed_args.quote_mode = 'none'
         sf.emit_list(c, data, output, parsed_args)
@@ -46,7 +45,7 @@ class TestCSVFormatter(unittest.TestCase):
         d2 = ('D', 'E', 'F')
         data = [d1, d2]
         expected = '"a","b","c"\n"A","B","C"\n"D","E","F"\n'
-        output = six.StringIO()
+        output = io.StringIO()
         # Parse arguments as if passed on the command-line
         parser = argparse.ArgumentParser(description='Testing...')
         sf.add_argument_group(parser)
@@ -61,7 +60,7 @@ class TestCSVFormatter(unittest.TestCase):
         d1 = ('A', 'B', test_columns.FauxColumn(['the', 'value']))
         data = [d1]
         expected = 'a,b,c\nA,B,[\'the\'\\, \'value\']\n'
-        output = six.StringIO()
+        output = io.StringIO()
         parsed_args = mock.Mock()
         parsed_args.quote_mode = 'none'
         sf.emit_list(c, data, output, parsed_args)
@@ -76,11 +75,9 @@ class TestCSVFormatter(unittest.TestCase):
         d2 = (u'D', u'E', happy)
         data = [d1, d2]
         expected = u'a,b,c\nA,B,C\nD,E,%s\n' % happy
-        output = six.StringIO()
+        output = io.StringIO()
         parsed_args = mock.Mock()
         parsed_args.quote_mode = 'none'
         sf.emit_list(c, data, output, parsed_args)
         actual = output.getvalue()
-        if six.PY2:
-            actual = actual.decode('utf-8')
         self.assertEqual(expected, actual)
diff --git a/cliff/tests/test_formatters_json.py b/cliff/tests/test_formatters_json.py
index 95e3218..c57412a 100644
--- a/cliff/tests/test_formatters_json.py
+++ b/cliff/tests/test_formatters_json.py
@@ -12,15 +12,14 @@
 #  License for the specific language governing permissions and limitations
 #  under the License.
 
+import io
 import json
+from unittest import mock
 
 from cliff.formatters import json_format
 from cliff.tests import base
 from cliff.tests import test_columns
 
-import six
-from unittest import mock
-
 
 class TestJSONFormatter(base.TestBase):
 
@@ -38,7 +37,7 @@ class TestJSONFormatter(base.TestBase):
         sf.add_argument_group(args)
 
         args.noindent = True
-        output = six.StringIO()
+        output = io.StringIO()
         sf.emit_one(c, d, output, args)
         value = output.getvalue()
         print(len(value.splitlines()))
@@ -47,7 +46,7 @@ class TestJSONFormatter(base.TestBase):
         self.assertEqual(expected, actual)
 
         args.noindent = False
-        output = six.StringIO()
+        output = io.StringIO()
         sf.emit_one(c, d, output, args)
         value = output.getvalue()
         self.assertEqual(6, len(value.splitlines()))
@@ -68,7 +67,7 @@ class TestJSONFormatter(base.TestBase):
         sf.add_argument_group(args)
 
         args.noindent = True
-        output = six.StringIO()
+        output = io.StringIO()
         sf.emit_one(c, d, output, args)
         value = output.getvalue()
         print(len(value.splitlines()))
@@ -93,7 +92,7 @@ class TestJSONFormatter(base.TestBase):
         sf.add_argument_group(args)
 
         args.noindent = True
-        output = six.StringIO()
+        output = io.StringIO()
         sf.emit_list(c, d, output, args)
         value = output.getvalue()
         self.assertEqual(1, len(value.splitlines()))
@@ -101,7 +100,7 @@ class TestJSONFormatter(base.TestBase):
         self.assertEqual(expected, actual)
 
         args.noindent = False
-        output = six.StringIO()
+        output = io.StringIO()
         sf.emit_list(c, d, output, args)
         value = output.getvalue()
         self.assertEqual(17, len(value.splitlines()))
@@ -121,7 +120,7 @@ class TestJSONFormatter(base.TestBase):
         sf.add_argument_group(args)
 
         args.noindent = True
-        output = six.StringIO()
+        output = io.StringIO()
         sf.emit_list(c, d, output, args)
         value = output.getvalue()
         self.assertEqual(1, len(value.splitlines()))
diff --git a/cliff/tests/test_formatters_shell.py b/cliff/tests/test_formatters_shell.py
index 01b4e84..896fe10 100644
--- a/cliff/tests/test_formatters_shell.py
+++ b/cliff/tests/test_formatters_shell.py
@@ -13,8 +13,7 @@
 #  under the License.
 
 import argparse
-import six
-
+import io
 from unittest import mock
 
 from cliff.formatters import shell
@@ -29,7 +28,7 @@ class TestShellFormatter(base.TestBase):
         c = ('a', 'b', 'c', 'd')
         d = ('A', 'B', 'C', '"escape me"')
         expected = 'a="A"\nb="B"\nd="\\"escape me\\""\n'
-        output = six.StringIO()
+        output = io.StringIO()
         args = mock.Mock()
         args.variables = ['a', 'b', 'd']
         args.prefix = ''
@@ -42,7 +41,7 @@ class TestShellFormatter(base.TestBase):
         c = ('a', 'b', 'c', 'd')
         d = ('A', 'B', 'C', '"escape me"')
         expected = 'Xd="\\"escape me\\""\n'
-        output = six.StringIO()
+        output = io.StringIO()
         # Parse arguments as if passed on the command-line
         parser = argparse.ArgumentParser(description='Testing...')
         sf.add_argument_group(parser)
@@ -60,7 +59,7 @@ class TestShellFormatter(base.TestBase):
             'b="B"',
             'c="[\'the\', \'value\']"\n',
         ])
-        output = six.StringIO()
+        output = io.StringIO()
         args = mock.Mock()
         args.variables = ['a', 'b', 'c']
         args.prefix = ''
@@ -71,10 +70,10 @@ class TestShellFormatter(base.TestBase):
     def test_non_string_values(self):
         sf = shell.ShellFormatter()
         c = ('a', 'b', 'c', 'd', 'e')
-        d = (True, False, 100, '"esc"', six.text_type('"esc"'))
+        d = (True, False, 100, '"esc"', str('"esc"'))
         expected = ('a="True"\nb="False"\nc="100"\n'
                     'd="\\"esc\\""\ne="\\"esc\\""\n')
-        output = six.StringIO()
+        output = io.StringIO()
         args = mock.Mock()
         args.variables = ['a', 'b', 'c', 'd', 'e']
         args.prefix = ''
@@ -87,7 +86,7 @@ class TestShellFormatter(base.TestBase):
         c = ('a', 'foo-bar', 'provider:network_type')
         d = (True, 'baz', 'vxlan')
         expected = 'a="True"\nfoo_bar="baz"\nprovider_network_type="vxlan"\n'
-        output = six.StringIO()
+        output = io.StringIO()
         args = mock.Mock()
         args.variables = ['a', 'foo-bar', 'provider:network_type']
         args.prefix = ''
diff --git a/cliff/tests/test_formatters_table.py b/cliff/tests/test_formatters_table.py
index a11ff43..2c0854d 100644
--- a/cliff/tests/test_formatters_table.py
+++ b/cliff/tests/test_formatters_table.py
@@ -16,7 +16,7 @@ import argparse
 import os
 import textwrap
 
-from six import StringIO
+from io import StringIO
 from unittest import mock
 
 from cliff.formatters import table
diff --git a/cliff/tests/test_formatters_value.py b/cliff/tests/test_formatters_value.py
index 6053dd3..a0f2362 100644
--- a/cliff/tests/test_formatters_value.py
+++ b/cliff/tests/test_formatters_value.py
@@ -12,7 +12,7 @@
 #  License for the specific language governing permissions and limitations
 #  under the License.
 
-import six
+from io import StringIO
 
 from cliff.formatters import value
 from cliff.tests import base
@@ -26,7 +26,7 @@ class TestValueFormatter(base.TestBase):
         c = ('a', 'b', 'c', 'd')
         d = ('A', 'B', 'C', '"no escape me"')
         expected = 'A\nB\nC\n"no escape me"\n'
-        output = six.StringIO()
+        output = StringIO()
         sf.emit_one(c, d, output, None)
         actual = output.getvalue()
         self.assertEqual(expected, actual)
@@ -36,7 +36,7 @@ class TestValueFormatter(base.TestBase):
         c = ('a', 'b', 'c', 'd')
         d = ('A', 'B', 'C', test_columns.FauxColumn(['the', 'value']))
         expected = "A\nB\nC\n['the', 'value']\n"
-        output = six.StringIO()
+        output = StringIO()
         sf.emit_one(c, d, output, None)
         actual = output.getvalue()
         self.assertEqual(expected, actual)
@@ -48,7 +48,7 @@ class TestValueFormatter(base.TestBase):
         d2 = ('D', 'E', 'F')
         data = [d1, d2]
         expected = 'A B C\nD E F\n'
-        output = six.StringIO()
+        output = StringIO()
         sf.emit_list(c, data, output, None)
         actual = output.getvalue()
         self.assertEqual(expected, actual)
@@ -59,7 +59,7 @@ class TestValueFormatter(base.TestBase):
         d1 = ('A', 'B', test_columns.FauxColumn(['the', 'value']))
         data = [d1]
         expected = "A B ['the', 'value']\n"
-        output = six.StringIO()
+        output = StringIO()
         sf.emit_list(c, data, output, None)
         actual = output.getvalue()
         self.assertEqual(expected, actual)
diff --git a/cliff/tests/test_formatters_yaml.py b/cliff/tests/test_formatters_yaml.py
index a76be85..5d741e2 100644
--- a/cliff/tests/test_formatters_yaml.py
+++ b/cliff/tests/test_formatters_yaml.py
@@ -12,7 +12,7 @@
 #  License for the specific language governing permissions and limitations
 #  under the License.
 
-import six
+from io import StringIO
 import yaml
 
 from unittest import mock
@@ -34,7 +34,7 @@ class TestYAMLFormatter(base.TestBase):
             'c': 'C',
             'd': '"escape me"'
         }
-        output = six.StringIO()
+        output = StringIO()
         args = mock.Mock()
         sf.emit_one(c, d, output, args)
         actual = yaml.safe_load(output.getvalue())
@@ -54,7 +54,7 @@ class TestYAMLFormatter(base.TestBase):
         sf.add_argument_group(args)
 
         args.noindent = True
-        output = six.StringIO()
+        output = StringIO()
         sf.emit_one(c, d, output, args)
         value = output.getvalue()
         print(len(value.splitlines()))
@@ -74,7 +74,7 @@ class TestYAMLFormatter(base.TestBase):
             {'a': 'A2', 'b': 'B2', 'c': 'C2'},
             {'a': 'A3', 'b': 'B3', 'c': 'C3'}
         ]
-        output = six.StringIO()
+        output = StringIO()
         args = mock.Mock()
         sf.add_argument_group(args)
         sf.emit_list(c, d, output, args)
@@ -94,7 +94,7 @@ class TestYAMLFormatter(base.TestBase):
         sf.add_argument_group(args)
 
         args.noindent = True
-        output = six.StringIO()
+        output = StringIO()
         sf.emit_list(c, d, output, args)
         actual = yaml.safe_load(output.getvalue())
         self.assertEqual(expected, actual)
diff --git a/cliff/tests/test_help.py b/cliff/tests/test_help.py
index 8b40d58..9034779 100644
--- a/cliff/tests/test_help.py
+++ b/cliff/tests/test_help.py
@@ -10,10 +10,7 @@
 #  License for the specific language governing permissions and limitations
 #  under the License.
 
-try:
-    from StringIO import StringIO
-except ImportError:
-    from io import StringIO
+import io
 import os
 import sys
 
@@ -32,7 +29,7 @@ class TestHelp(base.TestBase):
         # FIXME(dhellmann): Are commands tied too closely to the app? Or
         # do commands know too much about apps by using them to get to the
         # command manager?
-        stdout = StringIO()
+        stdout = io.StringIO()
         app = application.App('testing', '1',
                               utils.TestCommandManager(utils.TEST_NAMESPACE),
                               stdout=stdout)
@@ -50,7 +47,7 @@ class TestHelp(base.TestBase):
         # FIXME(dhellmann): Are commands tied too closely to the app? Or
         # do commands know too much about apps by using them to get to the
         # command manager?
-        stdout = StringIO()
+        stdout = io.StringIO()
         app = application.App('testing', '1',
                               utils.TestCommandManager(utils.TEST_NAMESPACE),
                               stdout=stdout)
@@ -70,7 +67,7 @@ class TestHelp(base.TestBase):
         # FIXME(dhellmann): Are commands tied too closely to the app? Or
         # do commands know too much about apps by using them to get to the
         # command manager?
-        stdout = StringIO()
+        stdout = io.StringIO()
         app = application.App('testing', '1',
                               utils.TestCommandManager(utils.TEST_NAMESPACE),
                               stdout=stdout)
@@ -88,7 +85,7 @@ class TestHelp(base.TestBase):
         # FIXME(dhellmann): Are commands tied too closely to the app? Or
         # do commands know too much about apps by using them to get to the
         # command manager?
-        stdout = StringIO()
+        stdout = io.StringIO()
         app = application.App('testing', '1',
                               utils.TestCommandManager(utils.TEST_NAMESPACE),
                               stdout=stdout)
@@ -115,7 +112,7 @@ class TestHelp(base.TestBase):
         # FIXME(dhellmann): Are commands tied too closely to the app? Or
         # do commands know too much about apps by using them to get to the
         # command manager?
-        stdout = StringIO()
+        stdout = io.StringIO()
         app = application.App('testing', '1',
                               utils.TestCommandManager(utils.TEST_NAMESPACE),
                               stdout=stdout)
@@ -132,7 +129,7 @@ class TestHelp(base.TestBase):
     @mock.patch.object(commandmanager.EntryPointWrapper, 'load',
                        side_effect=Exception('Could not load EntryPoint'))
     def test_show_help_with_ep_load_fail(self, mock_load):
-        stdout = StringIO()
+        stdout = io.StringIO()
         app = application.App('testing', '1',
                               utils.TestCommandManager(utils.TEST_NAMESPACE),
                               stdout=stdout)
@@ -154,7 +151,7 @@ class TestHelp(base.TestBase):
     @mock.patch.object(commandmanager.EntryPointWrapper, 'load',
                        side_effect=Exception('Could not load EntryPoint'))
     def test_show_help_print_exc_with_ep_load_fail(self, mock_load):
-        stdout = StringIO()
+        stdout = io.StringIO()
         app = application.App('testing', '1',
                               utils.TestCommandManager(utils.TEST_NAMESPACE),
                               stdout=stdout)
diff --git a/cliff/tests/test_utils.py b/cliff/tests/test_utils.py
index 6f4e29d..3699a75 100644
--- a/cliff/tests/test_utils.py
+++ b/cliff/tests/test_utils.py
@@ -14,11 +14,10 @@
 
 import os
 import sys
-
 from unittest import mock
 
-from cliff import utils
 from cliff.tests import base
+from cliff import utils
 
 
 class TestTerminalWidth(base.TestBase):
diff --git a/cliff/utils.py b/cliff/utils.py
index 0da9b42..cee1087 100644
--- a/cliff/utils.py
+++ b/cliff/utils.py
@@ -11,15 +11,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import codecs
 import ctypes
 import inspect
 import os
 import struct
 import sys
 
-import six
-
 # Each edit operation is assigned different cost, such as:
 #  'w' means swap operation, the cost is 0;
 #  's' means substitution operation, the cost is 2;
@@ -163,52 +160,3 @@ def _get_terminal_width_ioctl(stdout):
         return columns
     except IOError:
         return None
-
-
-if six.PY2:
-    def getwriter(encoding):
-        '''Override codecs.getwriter() to prevent codec errors.
-
-        The StreamWriter returned by codecs.getwriter has an unfortunate
-        property, it will attempt to encode every object presented to it's
-        write() function. Normally we only want unicode objects to be
-        encoded to a byte stream. If bytes are presented (e.g. str in
-        Python2) we make the assumption those bytes represent an already
-        encoded text stream or they are indeed binary bytes and hence
-        should not be encoded.
-
-        When the core StreamWriter attempts to encode a str object Python
-        will first promote the str object to a unicode object. The
-        promotion of str to unicode requires the str bytes to be
-        decoded. However the encoding associated with the str object is
-        not known therefore Python applies the default-encoding which is
-        ASCII. In the case where the str object contains utf-8 encoded
-        non-ASCII characters a decoding error is raised. By not attempting
-        to encode a byte stream we avoid this error.
-
-        It really does not make much sense to try and encode a byte
-        stream. First of all a byte stream should not be encoded if it's
-        not text (e.g. binary data). If the byte stream is encoded text
-        the only way to re-encode it is if we known it's encoding so we
-        can decode it into a canonical form (e.g. unicode). Thus to
-        re-encode it we encode from the canonical form (e.g. unicode) to
-        the new binary encoding. The problem in Python2 is we never know
-        if the bytes in a str object are text or binary data and if it's
-        text which encoding it is, hence we should not try to apply
-        an encoding to a str object.
-        '''
-        class _StreamWriter(codecs.StreamWriter):
-            def __init__(self, stream, errors='strict'):
-                codecs.StreamWriter.__init__(self, stream, errors)
-
-            def encode(self, msg, errors='strict'):
-                if isinstance(msg, six.text_type):
-                    return self.encoder(msg, errors)
-                return msg, len(msg)
-
-        _StreamWriter.encoder = codecs.getencoder(encoding)
-        _StreamWriter.encoding = encoding
-        return _StreamWriter
-
-else:
-    getwriter = codecs.getwriter
diff --git a/lower-constraints.txt b/lower-constraints.txt
index f98d024..8dd8957 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -21,7 +21,6 @@ python-subunit==1.0.0
 pytz==2013.6
 PyYAML==3.12
 requests==2.14.2
-six==1.10.0
 smmap==0.9.0
 snowballstemmer==1.2.1
 Sphinx==2.0.0
diff --git a/requirements.txt b/requirements.txt
index 1f87db9..cb74608 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,6 +5,5 @@ pbr!=2.1.0,>=2.0.0 # Apache-2.0
 cmd2>=0.8.0,!=0.8.3 # MIT
 PrettyTable<0.8,>=0.7.2 # BSD
 pyparsing>=2.1.0 # MIT
-six>=1.10.0 # MIT
 stevedore>=2.0.1 # Apache-2.0
 PyYAML>=3.12 # MIT