Rip some of the six imports from the codebase

15 files changed, 56 insertions, 103 deletions

diff --git a/pylint/checkers/base.py b/pylint/checkers/base.py
index 75ee08aff..69e8deced 100644
--- a/pylint/checkers/base.py
+++ b/pylint/checkers/base.py
@@ -28,14 +28,12 @@
 
 """basic checker for Python code"""
 
+import builtins
 import collections
 import itertools
 import sys
 import re
 
-import six
-from six.moves import zip  # pylint: disable=redefined-builtin
-
 import astroid
 import astroid.bases
 import astroid.scoped_nodes
@@ -134,7 +132,7 @@ TYPECHECK_COMPARISON_OPERATORS = frozenset(('is', 'is not', '==',
                                             '!=', 'in', 'not in'))
 LITERAL_NODE_TYPES = (astroid.Const, astroid.Dict, astroid.List, astroid.Set)
 UNITTEST_CASE = 'unittest.case'
-BUILTINS = six.moves.builtins.__name__
+BUILTINS = builtins.__name__
 TYPE_QNAME = "%s.type" % BUILTINS
 PY33 = sys.version_info >= (3, 3)
 PY3K = sys.version_info >= (3, 0)
@@ -879,8 +877,7 @@ functions, methods
     def visit_expr(self, node):
         """check for various kind of statements without effect"""
         expr = node.value
-        if isinstance(expr, astroid.Const) and isinstance(expr.value,
-                                                          six.string_types):
+        if isinstance(expr, astroid.Const) and isinstance(expr.value, str):
             # treat string statement in a separated message
             # Handle PEP-257 attribute docstrings.
             # An attribute docstring is defined as being a string right after
@@ -1385,12 +1382,12 @@ class NameChecker(_BasicChecker):
         self._bad_names = {}
 
     def leave_module(self, node): # pylint: disable=unused-argument
-        for all_groups in six.itervalues(self._bad_names):
+        for all_groups in self._bad_names.values():
             if len(all_groups) < 2:
                 continue
             groups = collections.defaultdict(list)
             min_warnings = sys.maxsize
-            for group in six.itervalues(all_groups):
+            for group in all_groups.values():
                 groups[len(group)].append(group)
                 min_warnings = min(len(group), min_warnings)
             if len(groups[min_warnings]) > 1:
@@ -1406,7 +1403,7 @@ class NameChecker(_BasicChecker):
     def visit_classdef(self, node):
         self._check_assign_to_new_keyword_violation(node.name, node)
         self._check_name('class', node.name, node)
-        for attr, anodes in six.iteritems(node.instance_attrs):
+        for attr, anodes in node.instance_attrs.items():
             if not any(node.instance_attr_ancestors(attr)):
                 self._check_name('attr', attr, anodes[0])
 
diff --git a/pylint/checkers/classes.py b/pylint/checkers/classes.py
index 2216d703b..5cbcb63e4 100644
--- a/pylint/checkers/classes.py
+++ b/pylint/checkers/classes.py
@@ -26,10 +26,9 @@
 from __future__ import generators
 
 import collections
+from itertools import zip_longest
 import sys
 
-import six
-
 import astroid
 from astroid.bases import Generator, BUILTINS
 from astroid.exceptions import InconsistentMroError, DuplicateBasesError
@@ -223,7 +222,7 @@ def _has_different_parameters_default_value(original, overridden):
     return False
 
 def _has_different_parameters(original, overridden, dummy_parameter_regex):
-    zipped = six.moves.zip_longest(original, overridden)
+    zipped = zip_longest(original, overridden)
     for original_param, overridden_param in zipped:
         params = (original_param, overridden_param)
         if not all(params):
@@ -403,7 +402,7 @@ def _has_same_layout_slots(slots, assigned_value):
     if isinstance(inferred, astroid.ClassDef):
         other_slots = inferred.slots()
         if all(first_slot and second_slot and first_slot.value == second_slot.value
-               for (first_slot, second_slot) in six.moves.zip_longest(slots, other_slots)):
+               for (first_slot, second_slot) in zip_longest(slots, other_slots)):
             return True
     return False
 
@@ -692,7 +691,7 @@ a metaclass class method.'}
             return
         defining_methods = self.config.defining_attr_methods
         current_module = cnode.root()
-        for attr, nodes in six.iteritems(cnode.instance_attrs):
+        for attr, nodes in cnode.instance_attrs.items():
             # skip nodes which are not in the current module and it may screw up
             # the output, while it's not worth it
             nodes = [n for n in nodes if not
@@ -905,7 +904,7 @@ a metaclass class method.'}
             if infered is astroid.Uninferable:
                 continue
             if (not isinstance(infered, astroid.Const) or
-                    not isinstance(infered.value, six.string_types)):
+                    not isinstance(infered.value, str)):
                 self.add_message('invalid-slots-object',
                                  args=infered.as_string(),
                                  node=elt)
@@ -932,7 +931,7 @@ a metaclass class method.'}
                     and not (node.is_abstract() or
                              overrides_a_method(class_node, node.name) or
                              decorated_with_property(node) or
-                             (six.PY3 and _has_bare_super_call(node)))):
+                             _has_bare_super_call(node))):
                 self.add_message('no-self-use', node=node)
 
     def visit_attribute(self, node):
@@ -1115,7 +1114,7 @@ a metaclass class method.'}
         """check that accessed members are defined"""
         # XXX refactor, probably much simpler now that E0201 is in type checker
         excs = ('AttributeError', 'Exception', 'BaseException')
-        for attr, nodes in six.iteritems(accessed):
+        for attr, nodes in accessed.items():
             try:
                 # is it a class attribute ?
                 node.local_attr(attr)
@@ -1299,7 +1298,7 @@ a metaclass class method.'}
                                              node=expr, args=klass.name)
             except astroid.InferenceError:
                 continue
-        for klass, method in six.iteritems(not_called_yet):
+        for klass, method in not_called_yet.items():
             cls = node_frame_class(method)
             if klass.name == 'object' or (cls and cls.name == 'object'):
                 continue
@@ -1493,7 +1492,7 @@ class SpecialMethodsChecker(BaseChecker):
             return
 
         value = inferred.value
-        if not isinstance(value, six.integer_types) or value < 0:
+        if not isinstance(value, int) or value < 0:
             self.add_message('invalid-length-returned', node=node)
 
 
diff --git a/pylint/checkers/exceptions.py b/pylint/checkers/exceptions.py
index 88d1b1a83..08fb6d8e8 100644
--- a/pylint/checkers/exceptions.py
+++ b/pylint/checkers/exceptions.py
@@ -18,12 +18,10 @@
 # For details: https://github.com/PyCQA/pylint/blob/master/COPYING
 
 """Checks for various exception related errors."""
-
+import builtins
 import inspect
 import sys
 
-import six
-from six.moves import builtins
 
 import astroid
 from pylint import checkers
@@ -35,7 +33,7 @@ def _builtin_exceptions():
     def predicate(obj):
         return isinstance(obj, type) and issubclass(obj, BaseException)
 
-    members = inspect.getmembers(six.moves.builtins, predicate)
+    members = inspect.getmembers(builtins, predicate)
     return {exc.__name__ for (_, exc) in members}
 
 
@@ -162,7 +160,7 @@ class ExceptionRaiseRefVisitor(BaseVisitor):
             self.visit_name(call.func)
         if (len(call.args) > 1 and
                 isinstance(call.args[0], astroid.Const) and
-                isinstance(call.args[0].value, six.string_types)):
+                isinstance(call.args[0].value, str)):
             msg = call.args[0].value
             if ('%' in msg or
                     ('{' in msg and '}' in msg)):
diff --git a/pylint/checkers/format.py b/pylint/checkers/format.py
index 2931f8eac..013ed47e3 100644
--- a/pylint/checkers/format.py
+++ b/pylint/checkers/format.py
@@ -39,9 +39,6 @@ import sys
 import tokenize
 from functools import reduce # pylint: disable=redefined-builtin
 
-import six
-from six.moves import zip, map, filter # pylint: disable=redefined-builtin
-
 from astroid import nodes
 
 from pylint.interfaces import ITokenChecker, IAstroidChecker, IRawChecker
@@ -894,8 +891,7 @@ class FormatChecker(BaseTokenChecker):
 
         for indent_pos, state, offsets in self._current_line.retained_warnings:
             block_type = offsets[tokens.start_col(indent_pos)]
-            hints = dict((k, v) for k, v in six.iteritems(offsets)
-                         if v != block_type)
+            hints = {k: v for k, v in offsets.items() if v != block_type}
             if single_line_block_stmt and block_type == WITH_BODY:
                 self._add_continuation_message(state, hints, tokens, indent_pos)
             elif not single_line_block_stmt and block_type == SINGLE_LINE:
diff --git a/pylint/checkers/imports.py b/pylint/checkers/imports.py
index 630090c41..9f3776d88 100644
--- a/pylint/checkers/imports.py
+++ b/pylint/checkers/imports.py
@@ -32,8 +32,6 @@ import os
 import sys
 import copy
 
-import six
-
 import astroid
 from astroid import are_exclusive
 from astroid.modutils import (get_module_part, is_standard_module)
@@ -164,14 +162,14 @@ def _dependencies_graph(filename, dep_info):
     done = {}
     printer = DotBackend(filename[:-4], rankdir='LR')
     printer.emit('URL="." node[shape="box"]')
-    for modname, dependencies in sorted(six.iteritems(dep_info)):
+    for modname, dependencies in sorted(dep_info.items()):
         done[modname] = 1
         printer.emit_node(modname)
         for depmodname in dependencies:
             if depmodname not in done:
                 done[depmodname] = 1
                 printer.emit_node(depmodname)
-    for depmodname, dependencies in sorted(six.iteritems(dep_info)):
+    for depmodname, dependencies in sorted(dep_info.items()):
         for modname in dependencies:
             printer.emit_edge(modname, depmodname)
     printer.generate(filename)
@@ -261,9 +259,7 @@ class ImportsChecker(BaseChecker):
     msgs = MSGS
     priority = -2
 
-    if six.PY2:
-        deprecated_modules = ('regsub', 'TERMIOS', 'Bastion', 'rexec')
-    elif sys.version_info < (3, 5):
+    if sys.version_info < (3, 5):
         deprecated_modules = ('optparse', )
     else:
         deprecated_modules = ('optparse', 'tkinter.tix')
@@ -739,7 +735,7 @@ class ImportsChecker(BaseChecker):
 
     def _report_external_dependencies(self, sect, _, _dummy):
         """return a verbatim layout for displaying dependencies"""
-        dep_info = _make_tree_defs(six.iteritems(self._external_dependencies_info()))
+        dep_info = _make_tree_defs(self._external_dependencies_info().items())
         if not dep_info:
             raise EmptyReportError()
         tree_str = _repr_tree_defs(dep_info)
@@ -771,7 +767,7 @@ class ImportsChecker(BaseChecker):
         if self.__ext_dep_info is None:
             package = self.linter.current_name
             self.__ext_dep_info = result = {}
-            for importee, importers in six.iteritems(self.stats['dependencies']):
+            for importee, importers in self.stats['dependencies'].items():
                 if not importee.startswith(package):
                     result[importee] = importers
         return self.__ext_dep_info
@@ -783,7 +779,7 @@ class ImportsChecker(BaseChecker):
         if self.__int_dep_info is None:
             package = self.linter.current_name
             self.__int_dep_info = result = {}
-            for importee, importers in six.iteritems(self.stats['dependencies']):
+            for importee, importers in self.stats['dependencies'].items():
                 if importee.startswith(package):
                     result[importee] = importers
         return self.__int_dep_info
diff --git a/pylint/checkers/logging.py b/pylint/checkers/logging.py
index 051fa7589..4cc3c30f8 100644
--- a/pylint/checkers/logging.py
+++ b/pylint/checkers/logging.py
@@ -17,8 +17,6 @@
 """
 import string
 
-import six
-
 import astroid
 
 from pylint import checkers
@@ -226,7 +224,7 @@ class LoggingChecker(checkers.BaseChecker):
             # don't check any further.
             return
         format_string = node.args[format_arg].value
-        if not isinstance(format_string, six.string_types):
+        if not isinstance(format_string, str):
             # If the log format is constant non-string (e.g. logging.debug(5)),
             # ensure there are no arguments.
             required_num_args = 0
@@ -261,7 +259,7 @@ def is_complex_format_str(node):
         bool: True if inferred string uses complex formatting, False otherwise
     """
     inferred = utils.safe_infer(node)
-    if inferred is None or not isinstance(inferred.value, six.string_types):
+    if inferred is None or not isinstance(inferred.value, str):
         return True
     for _, _, format_spec, _ in string.Formatter().parse(inferred.value):
         if format_spec:
diff --git a/pylint/checkers/misc.py b/pylint/checkers/misc.py
index 4f5407b10..c0f9ae83b 100644
--- a/pylint/checkers/misc.py
+++ b/pylint/checkers/misc.py
@@ -21,8 +21,6 @@
 
 import re
 
-import six
-
 from pylint.interfaces import IRawChecker
 from pylint.checkers import BaseChecker
 from pylint.utils import OPTION_RGX
@@ -111,7 +109,7 @@ class EncodingChecker(BaseChecker):
 
     def _check_encoding(self, lineno, line, file_encoding):
         try:
-            return six.text_type(line, file_encoding)
+            line.decode(file_encoding)
         except UnicodeDecodeError as ex:
             self.add_message('invalid-encoded-data', line=lineno,
                              args=(file_encoding, ex.args[2]))
diff --git a/pylint/checkers/python3.py b/pylint/checkers/python3.py
index 8e0da4b88..9b36d68aa 100644
--- a/pylint/checkers/python3.py
+++ b/pylint/checkers/python3.py
@@ -21,14 +21,11 @@
 """Check Python 2 code for Python 2/3 source-compatible issues."""
 from __future__ import absolute_import, print_function
 
+from collections import namedtuple
 import re
 import sys
 import tokenize
 
-from collections import namedtuple
-
-import six
-
 import astroid
 from astroid import bases
 
@@ -644,7 +641,7 @@ class Python3Checker(checkers.BaseChecker):
         self.add_message('print-statement', node=node, always_warn=True)
 
     def _warn_if_deprecated(self, node, module, attributes, report_on_modules=True):
-        for message, module_map in six.iteritems(self._bad_python3_module_map):
+        for message, module_map in self._bad_python3_module_map.items():
             if module in module_map and module not in self._modules_warned_about:
                 if isinstance(module_map, frozenset):
                     if report_on_modules:
@@ -731,7 +728,7 @@ class Python3Checker(checkers.BaseChecker):
     @staticmethod
     def _is_constant_string_or_name(node):
         if isinstance(node, astroid.Const):
-            return isinstance(node.value, six.string_types)
+            return isinstance(node.value, str)
         return isinstance(node, astroid.Name)
 
     @staticmethod
@@ -749,7 +746,7 @@ class Python3Checker(checkers.BaseChecker):
             if inferred_type is astroid.Uninferable:
                 confidence = INFERENCE_FAILURE
             elif not (isinstance(inferred_type, astroid.Const) and
-                      isinstance(inferred_type.value, six.string_types)):
+                      isinstance(inferred_type.value, str)):
                 return None
         return confidence
 
diff --git a/pylint/checkers/refactoring.py b/pylint/checkers/refactoring.py
index 3ad179da2..1a3641ebb 100644
--- a/pylint/checkers/refactoring.py
+++ b/pylint/checkers/refactoring.py
@@ -15,14 +15,13 @@
 # For details: https://github.com/PyCQA/pylint/blob/master/COPYING
 
 """Looks for code which can be refactored."""
-
+import builtins
 import collections
 import itertools
 import tokenize
 
 import astroid
 from astroid import decorators
-import six
 
 from pylint import interfaces
 from pylint import checkers
@@ -253,7 +252,7 @@ class RefactoringChecker(checkers.BaseTokenChecker):
                 # tokens[index][2] is the actual position and also is
                 # reported by IronPython.
                 self._elifs.extend([tokens[index][2], tokens[index+1][2]])
-            elif six.PY3 and is_trailing_comma(tokens, index):
+            elif is_trailing_comma(tokens, index):
                 if self.linter.is_message_enabled('trailing-comma-tuple'):
                     self.add_message('trailing-comma-tuple',
                                      line=token.start[0])
@@ -728,7 +727,7 @@ class NotChecker(checkers.BaseChecker):
     # not equivalent to "set(LEFT_VALS) > set(RIGHT_VALS)"
     skipped_nodes = (astroid.Set,)
     # 'builtins' py3, '__builtin__' py2
-    skipped_classnames = ['%s.%s' % (six.moves.builtins.__name__, qname)
+    skipped_classnames = ['%s.%s' % (builtins.__name__, qname)
                           for qname in ('set', 'frozenset')]
 
     @utils.check_messages('unneeded-not')
diff --git a/pylint/checkers/similar.py b/pylint/checkers/similar.py
index 8fd993fb2..295a3828b 100644
--- a/pylint/checkers/similar.py
+++ b/pylint/checkers/similar.py
@@ -20,9 +20,6 @@ from __future__ import print_function
 import sys
 from collections import defaultdict
 
-import six
-from six.moves import zip
-
 from pylint.utils import decoding_stream
 from pylint.interfaces import IRawChecker
 from pylint.checkers import BaseChecker, table_lines_from_stats
@@ -72,7 +69,7 @@ class Similar(object):
             else:
                 duplicate.append(set([(lineset1, idx1), (lineset2, idx2)]))
         sims = []
-        for num, ensembles in six.iteritems(no_duplicates):
+        for num, ensembles in no_duplicates.items():
             for couples in ensembles:
                 sims.append((num, couples))
         sims.sort()
diff --git a/pylint/checkers/stdlib.py b/pylint/checkers/stdlib.py
index 37619cbb4..c1c3217d2 100644
--- a/pylint/checkers/stdlib.py
+++ b/pylint/checkers/stdlib.py
@@ -20,8 +20,6 @@
 
 import sys
 
-import six
-
 import astroid
 from astroid.bases import Instance
 from pylint.interfaces import IAstroidChecker
@@ -42,15 +40,12 @@ else:
 
 def _check_mode_str(mode):
     # check type
-    if not isinstance(mode, six.string_types):
+    if not isinstance(mode, str):
         return False
     # check syntax
     modes = set(mode)
-    _mode = "rwatb+U"
-    creating = False
-    if six.PY3:
-        _mode += "x"
-        creating = "x" in modes
+    _mode = "rwatb+Ux"
+    creating = "x" in modes
     if modes - set(_mode) or len(mode) > len(modes):
         return False
     # check logic
@@ -60,25 +55,16 @@ def _check_mode_str(mode):
     text = "t" in modes
     binary = "b" in modes
     if "U" in modes:
-        if writing or appending or creating and six.PY3:
+        if writing or appending or creating:
             return False
         reading = True
-        if not six.PY3:
-            binary = True
     if text and binary:
         return False
-    total = reading + writing + appending + (creating if six.PY3 else 0)
+    total = reading + writing + appending + creating
     if total > 1:
         return False
-    if not (reading or writing or appending or creating and six.PY3):
+    if not (reading or writing or appending or creating):
         return False
-    # other 2.x constraints
-    if not six.PY3:
-        if "U" in mode:
-            mode = mode.replace("U", "")
-            if "r" not in mode:
-                mode = "r" + mode
-        return mode[0] in ("r", "w", "a", "U")
     return True
 
 
diff --git a/pylint/checkers/strings.py b/pylint/checkers/strings.py
index 6a0ed9657..f82048800 100644
--- a/pylint/checkers/strings.py
+++ b/pylint/checkers/strings.py
@@ -25,8 +25,6 @@ import tokenize
 import string
 import numbers
 
-import six
-
 import astroid
 from pylint.interfaces import ITokenChecker, IAstroidChecker, IRawChecker
 from pylint.checkers import BaseChecker, BaseTokenChecker
@@ -252,7 +250,7 @@ class StringFormatChecker(BaseChecker):
         args = node.right
 
         if not (isinstance(left, astroid.Const)
-                and isinstance(left.value, six.string_types)):
+                and isinstance(left.value, str)):
             return
         format_string = left.value
         try:
@@ -281,7 +279,7 @@ class StringFormatChecker(BaseChecker):
                 for k, _ in args.items:
                     if isinstance(k, astroid.Const):
                         key = k.value
-                        if isinstance(key, six.string_types):
+                        if isinstance(key, str):
                             keys.add(key)
                         else:
                             self.add_message('bad-format-string-key',
@@ -372,7 +370,7 @@ class StringFormatChecker(BaseChecker):
             return
         if not isinstance(strnode, astroid.Const):
             return
-        if not isinstance(strnode.value, six.string_types):
+        if not isinstance(strnode.value, str):
             return
 
         if node.starargs or node.kwargs:
@@ -388,7 +386,7 @@ class StringFormatChecker(BaseChecker):
             return
 
         named_fields = set(field[0] for field in fields
-                           if isinstance(field[0], six.string_types))
+                           if isinstance(field[0], str))
         if num_args and manual_pos:
             self.add_message('format-combined-specification',
                              node=node)
diff --git a/pylint/checkers/typecheck.py b/pylint/checkers/typecheck.py
index bad33c667..28d374640 100644
--- a/pylint/checkers/typecheck.py
+++ b/pylint/checkers/typecheck.py
@@ -28,6 +28,7 @@
 """try to find more bugs in the code using astroid inference capabilities
 """
 
+import builtins
 import collections
 import fnmatch
 import heapq
@@ -37,8 +38,6 @@ import re
 import shlex
 import sys
 
-import six
-
 import astroid
 import astroid.context
 import astroid.arguments
@@ -65,16 +64,14 @@ from pylint.checkers.utils import (
     singledispatch)
 from pylint.utils import get_global_option
 
-BUILTINS = six.moves.builtins.__name__
+BUILTINS = builtins.__name__
 STR_FORMAT = {"%s.str.format" % BUILTINS}
-if six.PY2:
-    STR_FORMAT.add("%s.unicode.format" % BUILTINS)
 
 
 def _unflatten(iterable):
     for index, elem in enumerate(iterable):
         if (isinstance(elem, collections.Sequence) and
-                not isinstance(elem, six.string_types)):
+                not isinstance(elem, str)):
             for single_elem in _unflatten(elem):
                 yield single_elem
         elif elem and not index:
@@ -627,7 +624,7 @@ accessed. Python regular expressions are accepted.'}
         # (surrounded by quote `"` and followed by a comma `,`)
         # REQUEST,aq_parent,"[a-zA-Z]+_set{1,2}"' =>
         # ('REQUEST', 'aq_parent', '[a-zA-Z]+_set{1,2}')
-        if isinstance(self.config.generated_members, six.string_types):
+        if isinstance(self.config.generated_members, str):
             gen = shlex.shlex(self.config.generated_members)
             gen.whitespace += ','
             gen.wordchars += r'[]-+\.*?()|'
@@ -1149,7 +1146,7 @@ accessed. Python regular expressions are accepted.'}
                 # manager and give up, otherwise emit not-context-manager.
                 # See the test file for not_context_manager for a couple
                 # of self explaining tests.
-                for path in six.moves.filter(None, _unflatten(context.path)):
+                for path in filter(None, _unflatten(context.path)):
                     scope = path.scope()
                     if not isinstance(scope, astroid.FunctionDef):
                         continue
diff --git a/pylint/checkers/utils.py b/pylint/checkers/utils.py
index 9d8a18ba5..dfa6ddddb 100644
--- a/pylint/checkers/utils.py
+++ b/pylint/checkers/utils.py
@@ -40,7 +40,6 @@ import itertools
 import re
 import sys
 import string
-import warnings
 
 import six
 from six.moves import map, builtins # pylint: disable=redefined-builtin
diff --git a/pylint/checkers/variables.py b/pylint/checkers/variables.py
index 7b66eaa1d..edaa1547b 100644
--- a/pylint/checkers/variables.py
+++ b/pylint/checkers/variables.py
@@ -38,8 +38,6 @@ try:
 except ImportError:
     from backports.functools_lru_cache import lru_cache
 
-import six
-
 import astroid
 from astroid import decorators
 from astroid import modutils
@@ -181,7 +179,7 @@ def _fix_dot_imports(not_consumed):
     """
     # TODO: this should be improved in issue astroid #46
     names = {}
-    for name, stmts in six.iteritems(not_consumed):
+    for name, stmts in not_consumed.items():
         if any(isinstance(stmt, astroid.AssignName)
                and isinstance(stmt.assign_type(), astroid.AugAssign)
                for stmt in stmts):
@@ -499,7 +497,7 @@ class VariablesChecker(BaseChecker):
         checks globals doesn't overrides builtins
         """
         self._to_consume = [NamesConsumer(node, 'module')]
-        for name, stmts in six.iteritems(node.locals):
+        for name, stmts in node.locals.items():
             if utils.is_builtin(name) and not utils.is_inside_except(stmts[0]):
                 if self._should_ignore_redefined_builtin(stmts[0]):
                     continue
@@ -542,7 +540,7 @@ class VariablesChecker(BaseChecker):
                 continue
 
             if (not isinstance(elt_name, astroid.Const)
-                    or not isinstance(elt_name.value, six.string_types)):
+                    or not isinstance(elt_name.value, str)):
                 self.add_message('invalid-all-object',
                                  args=elt.as_string(), node=elt)
                 continue
@@ -577,7 +575,7 @@ class VariablesChecker(BaseChecker):
     def _check_globals(self, not_consumed):
         if self._allow_global_unused_variables:
             return
-        for name, nodes in six.iteritems(not_consumed):
+        for name, nodes in not_consumed.items():
             for node in nodes:
                 self.add_message('unused-variable', args=(name,), node=node)
 
@@ -810,7 +808,7 @@ class VariablesChecker(BaseChecker):
 
         global_names = _flattened_scope_names(node.nodes_of_class(astroid.Global))
         nonlocal_names = _flattened_scope_names(node.nodes_of_class(astroid.Nonlocal))
-        for name, stmts in six.iteritems(not_consumed):
+        for name, stmts in not_consumed.items():
             self._check_is_unused(name, node, stmts[0], global_names, nonlocal_names)
 
     visit_asyncfunctiondef = visit_functiondef