Remove six library

The tooz project doesn't support Python 2 anymore, using the
six library should not be necessary.

Change-Id: I9886cabcd13cbc615065ceb372efbf037dff1aeb

22 files changed, 54 insertions, 86 deletions

diff --git a/examples/group_membership.py b/examples/group_membership.py
index 7b85e6c..9f4bb97 100644
--- a/examples/group_membership.py
+++ b/examples/group_membership.py
@@ -1,14 +1,12 @@
 import uuid
 
-import six
-
 from tooz import coordination
 
 coordinator = coordination.get_coordinator('zake://', b'host-1')
 coordinator.start()
 
 # Create a group
-group = six.binary_type(six.text_type(uuid.uuid4()).encode('ascii'))
+group = bytes(str(uuid.uuid4()).encode('ascii'))
 request = coordinator.create_group(group)
 request.get()
 
diff --git a/examples/group_membership_watch.py b/examples/group_membership_watch.py
index 51836c2..b1118a6 100644
--- a/examples/group_membership_watch.py
+++ b/examples/group_membership_watch.py
@@ -1,14 +1,12 @@
 import uuid
 
-import six
-
 from tooz import coordination
 
 coordinator = coordination.get_coordinator('zake://', b'host-1')
 coordinator.start()
 
 # Create a group
-group = six.binary_type(six.text_type(uuid.uuid4()).encode('ascii'))
+group = bytes(str(uuid.uuid4()).encode('ascii'))
 request = coordinator.create_group(group)
 request.get()
 
diff --git a/examples/leader_election.py b/examples/leader_election.py
index 661c314..364e9bc 100644
--- a/examples/leader_election.py
+++ b/examples/leader_election.py
@@ -1,8 +1,6 @@
 import time
 import uuid
 
-import six
-
 from tooz import coordination
 
 ALIVE_TIME = 1
@@ -10,7 +8,7 @@ coordinator = coordination.get_coordinator('zake://', b'host-1')
 coordinator.start()
 
 # Create a group
-group = six.binary_type(six.text_type(uuid.uuid4()).encode('ascii'))
+group = bytes(str(uuid.uuid4()).encode('ascii'))
 request = coordinator.create_group(group)
 request.get()
 
diff --git a/requirements.txt b/requirements.txt
index c1f072c..a448b67 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,7 +3,6 @@
 # process, which may cause wedges in the gate later.
 pbr>=1.6 # Apache-2.0
 stevedore>=1.16.0 # Apache-2.0
-six>=1.9.0 # MIT
 voluptuous>=0.8.9 # BSD License
 msgpack>=0.4.0 # Apache-2.0
 fasteners>=0.7 # Apache-2.0
diff --git a/tooz/coordination.py b/tooz/coordination.py
index 99cdff0..d5ac941 100755
--- a/tooz/coordination.py
+++ b/tooz/coordination.py
@@ -21,11 +21,11 @@ from concurrent import futures
 import enum
 import logging
 import threading
+import urllib
 
 from oslo_utils import encodeutils
 from oslo_utils import netutils
 from oslo_utils import timeutils
-import six
 from stevedore import driver
 import tenacity
 
@@ -629,8 +629,7 @@ class CoordinationDriver(object):
         pass
 
 
-@six.add_metaclass(abc.ABCMeta)
-class CoordAsyncResult(object):
+class CoordAsyncResult(object, metaclass=abc.ABCMeta):
     """Representation of an asynchronous task.
 
     Every call API returns an CoordAsyncResult object on which the result or
@@ -786,12 +785,12 @@ def get_coordinator(backend_url, member_id,
                    arguments query string)
     """
     parsed_url = netutils.urlsplit(backend_url)
-    parsed_qs = six.moves.urllib.parse.parse_qs(parsed_url.query)
+    parsed_qs = urllib.parse.parse_qs(parsed_url.query)
     if kwargs:
         options = {}
-        for (k, v) in six.iteritems(kwargs):
+        for (k, v) in kwargs.items():
             options[k] = [v]
-        for (k, v) in six.iteritems(parsed_qs):
+        for (k, v) in parsed_qs.items():
             if k not in options:
                 options[k] = v
     else:
diff --git a/tooz/drivers/etcd.py b/tooz/drivers/etcd.py
index 45bacca..5d9a186 100644
--- a/tooz/drivers/etcd.py
+++ b/tooz/drivers/etcd.py
@@ -12,6 +12,7 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import functools
 import logging
 import threading
 
@@ -19,7 +20,6 @@ import fasteners
 from oslo_utils import encodeutils
 from oslo_utils import timeutils
 import requests
-import six
 
 import tooz
 from tooz import coordination
@@ -33,7 +33,7 @@ LOG = logging.getLogger(__name__)
 def _translate_failures(func):
     """Translates common requests exceptions into tooz exceptions."""
 
-    @six.wraps(func)
+    @functools.wraps(func)
     def wrapper(*args, **kwargs):
         try:
             return func(*args, **kwargs)
diff --git a/tooz/drivers/etcd3.py b/tooz/drivers/etcd3.py
index 8dcdaa7..1b708ee 100644
--- a/tooz/drivers/etcd3.py
+++ b/tooz/drivers/etcd3.py
@@ -18,7 +18,6 @@ import threading
 import etcd3
 from etcd3 import exceptions as etcd3_exc
 from oslo_utils import encodeutils
-import six
 
 import tooz
 from tooz import _retry
@@ -48,7 +47,7 @@ def _failure_translator():
 
 def _translate_failures(func):
 
-    @six.wraps(func)
+    @functools.wraps(func)
     def wrapper(*args, **kwargs):
         with _failure_translator():
             return func(*args, **kwargs)
diff --git a/tooz/drivers/etcd3gw.py b/tooz/drivers/etcd3gw.py
index 4b9cada..232b3ae 100644
--- a/tooz/drivers/etcd3gw.py
+++ b/tooz/drivers/etcd3gw.py
@@ -11,14 +11,15 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations
 # under the License.
+
 import base64
+import functools
 import threading
 import uuid
 
 import etcd3gw
 from etcd3gw import exceptions as etcd3_exc
 from oslo_utils import encodeutils
-import six
 
 import tooz
 from tooz import _retry
@@ -35,7 +36,7 @@ def _encode(data):
 def _translate_failures(func):
     """Translates common requests exceptions into tooz exceptions."""
 
-    @six.wraps(func)
+    @functools.wraps(func)
     def wrapper(*args, **kwargs):
         try:
             return func(*args, **kwargs)
diff --git a/tooz/drivers/file.py b/tooz/drivers/file.py
index 2ffa0a3..eb26eb0 100644
--- a/tooz/drivers/file.py
+++ b/tooz/drivers/file.py
@@ -32,7 +32,6 @@ import fasteners
 from oslo_utils import encodeutils
 from oslo_utils import fileutils
 from oslo_utils import timeutils
-import six
 import voluptuous
 
 import tooz
@@ -74,7 +73,7 @@ def _convert_from_old_format(data):
     # example of potential old python3 payload:
     # {u"member_id": b"member"}
     # {u"member_id": u"member"}
-    if six.PY3 and b"member_id" in data or b"group_id" in data:
+    if b"member_id" in data or b"group_id" in data:
         data = dict((k.decode("utf8"), v) for k, v in data.items())
         # About member_id and group_id valuse if the file have been written
         # with python2 and in the old format, we can't known with python3
@@ -91,7 +90,7 @@ def _lock_me(lock):
 
     def wrapper(func):
 
-        @six.wraps(func)
+        @functools.wraps(func)
         def decorator(*args, **kwargs):
             with lock:
                 return func(*args, **kwargs)
@@ -361,14 +360,12 @@ class FileDriver(coordination.CoordinationDriverCachedRunWatchers,
 
     _SCHEMAS = {
         'group': voluptuous.Schema({
-            voluptuous.Required('group_id'): voluptuous.Any(six.text_type,
-                                                            six.binary_type),
+            voluptuous.Required('group_id'): voluptuous.Any(str, bytes),
             # NOTE(sileht): tooz <1.36 was creating file without this
             voluptuous.Optional('encoded'): bool,
         }),
         'member': voluptuous.Schema({
-            voluptuous.Required('member_id'): voluptuous.Any(six.text_type,
-                                                             six.binary_type),
+            voluptuous.Required('member_id'): voluptuous.Any(str, bytes),
             voluptuous.Required('joined_on'): datetime.datetime,
             # NOTE(sileht): tooz <1.36 was creating file without this
             voluptuous.Optional('encoded'): bool,
diff --git a/tooz/drivers/ipc.py b/tooz/drivers/ipc.py
index 50885dc..bcb7a00 100644
--- a/tooz/drivers/ipc.py
+++ b/tooz/drivers/ipc.py
@@ -19,7 +19,6 @@ import struct
 import time
 
 import msgpack
-import six
 import sysv_ipc
 
 import tooz
@@ -37,10 +36,10 @@ def ftok(name, project):
     # Similar to ftok & http://semanchuk.com/philip/sysv_ipc/#ftok_weakness
     # but hopefully without as many weaknesses...
     h = hashlib.md5()
-    if not isinstance(project, six.binary_type):
+    if not isinstance(project, bytes):
         project = project.encode('ascii')
     h.update(project)
-    if not isinstance(name, six.binary_type):
+    if not isinstance(name, bytes):
         name = name.encode('ascii')
     h.update(name)
     return (int(h.hexdigest(), 16) % _KEY_RANGE) + sysv_ipc.KEY_MIN
diff --git a/tooz/drivers/memcached.py b/tooz/drivers/memcached.py
index ad409d1..1cefd95 100644
--- a/tooz/drivers/memcached.py
+++ b/tooz/drivers/memcached.py
@@ -22,7 +22,6 @@ import socket
 
 from oslo_utils import encodeutils
 from pymemcache import client as pymemcache_client
-import six
 
 import tooz
 from tooz import _retry
@@ -65,7 +64,7 @@ def _failure_translator():
 
 def _translate_failures(func):
 
-    @six.wraps(func)
+    @functools.wraps(func)
     def wrapper(*args, **kwargs):
         with _failure_translator():
             return func(*args, **kwargs)
@@ -266,7 +265,7 @@ class MemcachedDriver(coordination.CoordinationDriverCachedRunWatchers,
 
     @staticmethod
     def _msgpack_serializer(key, value):
-        if isinstance(value, six.binary_type):
+        if isinstance(value, bytes):
             return value, 1
         return utils.dumps(value), 2
 
@@ -435,7 +434,7 @@ class MemcachedDriver(coordination.CoordinationDriverCachedRunWatchers,
         if group_members is None:
             raise coordination.GroupNotCreated(group_id)
         actual_group_members = {}
-        for m, v in six.iteritems(group_members):
+        for m, v in group_members.items():
             # Never kick self from the group, we know we're alive
             if (m == self._member_id or
                self.client.get(self._encode_member_id(m))):
@@ -512,7 +511,7 @@ class MemcachedDriver(coordination.CoordinationDriverCachedRunWatchers,
 
     @_translate_failures
     def run_elect_coordinator(self):
-        for group_id, hooks in six.iteritems(self._hooks_elected_leader):
+        for group_id, hooks in self._hooks_elected_leader.items():
             # Try to grab the lock, if that fails, that means someone has it
             # already.
             leader_lock = self._get_leader_lock(group_id)
diff --git a/tooz/drivers/pgsql.py b/tooz/drivers/pgsql.py
index 6c60a20..71b7ae3 100644
--- a/tooz/drivers/pgsql.py
+++ b/tooz/drivers/pgsql.py
@@ -20,7 +20,6 @@ import logging
 
 from oslo_utils import encodeutils
 import psycopg2
-import six
 
 import tooz
 from tooz import _retry
@@ -101,10 +100,7 @@ class PostgresLock(locking.Lock):
         self._options = options
         h = hashlib.md5()
         h.update(name)
-        if six.PY2:
-            self.key = list(map(ord, h.digest()[0:2]))
-        else:
-            self.key = h.digest()[0:2]
+        self.key = h.digest()[0:2]
 
     def acquire(self, blocking=True, shared=False):
 
diff --git a/tooz/drivers/redis.py b/tooz/drivers/redis.py
index f388f4d..0c01a1b 100644
--- a/tooz/drivers/redis.py
+++ b/tooz/drivers/redis.py
@@ -26,9 +26,6 @@ from oslo_utils import strutils
 import redis
 from redis import exceptions
 from redis import sentinel
-import six
-from six.moves import map as compat_map
-from six.moves import zip as compat_zip
 
 import tooz
 from tooz import coordination
@@ -55,7 +52,7 @@ def _translate_failures():
 
 class RedisLock(locking.Lock):
     def __init__(self, coord, client, name, timeout):
-        name = "%s_%s_lock" % (coord.namespace, six.text_type(name))
+        name = "%s_%s_lock" % (coord.namespace, str(name))
         super(RedisLock, self).__init__(name)
         # NOTE(jd) Make sure we don't release and heartbeat at the same time by
         # using a exclusive access lock (LP#1557593)
@@ -356,7 +353,7 @@ return 1
         self._scripts = {}
 
     def _check_fetch_redis_version(self, geq_version, not_existent=True):
-        if isinstance(geq_version, six.string_types):
+        if isinstance(geq_version, str):
             desired_version = version.LooseVersion(geq_version)
         elif isinstance(geq_version, version.LooseVersion):
             desired_version = geq_version
@@ -470,12 +467,12 @@ return 1
             # For py3.x ensure these are unicode since the string template
             # replacement will expect unicode (and we don't want b'' as a
             # prefix which will happen in py3.x if this is not done).
-            for (k, v) in six.iteritems(tpl_params.copy()):
-                if isinstance(v, six.binary_type):
+            for (k, v) in tpl_params.copy().items():
+                if isinstance(v, bytes):
                     v = v.decode('ascii')
                 tpl_params[k] = v
             prepared_scripts = {}
-            for name, raw_script_tpl in six.iteritems(self.SCRIPTS):
+            for name, raw_script_tpl in self.SCRIPTS.items():
                 script_tpl = string.Template(raw_script_tpl)
                 script = script_tpl.substitute(**tpl_params)
                 prepared_scripts[name] = self._client.register_script(script)
@@ -630,10 +627,10 @@ return 1
                 return set()
             # Ok now we need to see which members have passed away...
             gone_members = set()
-            member_values = p.mget(compat_map(self._encode_beat_id,
-                                              potential_members))
-            for (potential_member, value) in compat_zip(potential_members,
-                                                        member_values):
+            member_values = p.mget(map(self._encode_beat_id,
+                                       potential_members))
+            for (potential_member, value) in zip(potential_members,
+                                                 member_values):
                 # Always preserve self (just incase we haven't heartbeated
                 # while this call/s was being made...), this does *not* prevent
                 # another client from removing this though...
@@ -742,7 +739,7 @@ return 1
         return self.get_lock(name)
 
     def run_elect_coordinator(self):
-        for group_id, hooks in six.iteritems(self._hooks_elected_leader):
+        for group_id, hooks in self._hooks_elected_leader.items():
             leader_lock = self._get_leader_lock(group_id)
             if leader_lock.acquire(blocking=False):
                 # We got the lock
diff --git a/tooz/drivers/zookeeper.py b/tooz/drivers/zookeeper.py
index db57f19..e08708b 100644
--- a/tooz/drivers/zookeeper.py
+++ b/tooz/drivers/zookeeper.py
@@ -25,8 +25,6 @@ from kazoo.handlers import threading as threading_handler
 from kazoo.protocol import paths
 from oslo_utils import encodeutils
 from oslo_utils import strutils
-import six
-from six.moves import filter as compat_filter
 
 import tooz
 from tooz import coordination
@@ -444,7 +442,7 @@ class KazooDriver(coordination.CoordinationDriverCachedRunWatchers):
         args.extend(more_args)
         cleaned_args = []
         for arg in args:
-            if isinstance(arg, six.binary_type):
+            if isinstance(arg, bytes):
                 cleaned_args.append(arg.decode('ascii'))
             else:
                 cleaned_args.append(arg)
@@ -467,7 +465,7 @@ class KazooDriver(coordination.CoordinationDriverCachedRunWatchers):
             auth_data = None
 
         maybe_hosts = [parsed_url.netloc] + list(options.get('hosts', []))
-        hosts = list(compat_filter(None, maybe_hosts))
+        hosts = list(filter(None, maybe_hosts))
         if not hosts:
             hosts = ['localhost:2181']
         randomize_hosts = options.get('randomize_hosts', True)
@@ -520,7 +518,7 @@ class KazooDriver(coordination.CoordinationDriverCachedRunWatchers):
         return ZooKeeperLock(name, z_lock)
 
     def run_elect_coordinator(self):
-        for group_id in six.iterkeys(self._hooks_elected_leader):
+        for group_id in self._hooks_elected_leader.keys():
             leader_lock = self._get_group_leader_lock(group_id)
             if leader_lock.is_acquired:
                 # Previously acquired/still leader, leave it be...
diff --git a/tooz/hashring.py b/tooz/hashring.py
index bfe8638..51016f2 100644
--- a/tooz/hashring.py
+++ b/tooz/hashring.py
@@ -16,8 +16,6 @@
 import bisect
 import hashlib
 
-import six
-
 import tooz
 from tooz import utils
 
@@ -71,7 +69,7 @@ class HashRing(object):
         for node in nodes:
             key = utils.to_binary(node, 'utf-8')
             key_hash = hashlib.md5(key)
-            for r in six.moves.range(self._partition_number * weight):
+            for r in range(self._partition_number * weight):
                 key_hash.update(key)
                 self._ring[self._hash2int(key_hash)] = node
 
@@ -93,7 +91,7 @@ class HashRing(object):
 
         key = utils.to_binary(node, 'utf-8')
         key_hash = hashlib.md5(key)
-        for r in six.moves.range(self._partition_number * weight):
+        for r in range(self._partition_number * weight):
             key_hash.update(key)
             del self._ring[self._hash2int(key_hash)]
 
diff --git a/tooz/locking.py b/tooz/locking.py
index f4ae0f0..20890f6 100644
--- a/tooz/locking.py
+++ b/tooz/locking.py
@@ -15,8 +15,6 @@
 #    under the License.
 import abc
 
-import six
-
 import tooz
 from tooz import coordination
 
@@ -34,8 +32,7 @@ class _LockProxy(object):
         self.lock.__exit__(exc_type, exc_val, exc_tb)
 
 
-@six.add_metaclass(abc.ABCMeta)
-class Lock(object):
+class Lock(object, metaclass=abc.ABCMeta):
     def __init__(self, name):
         if not name:
             raise ValueError("Locks must be provided a name")
diff --git a/tooz/partitioner.py b/tooz/partitioner.py
index 63eaba0..3a23f9e 100644
--- a/tooz/partitioner.py
+++ b/tooz/partitioner.py
@@ -13,7 +13,7 @@
 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #    License for the specific language governing permissions and limitations
 #    under the License.
-import six
+
 from tooz import hashring
 
 
@@ -54,7 +54,7 @@ class Partitioner(object):
     def _hash_object(obj):
         if hasattr(obj, "__tooz_hash__"):
             return obj.__tooz_hash__()
-        return six.text_type(obj).encode('utf8')
+        return str(obj).encode('utf8')
 
     def members_for_object(self, obj, ignore_members=None, replicas=1):
         """Return the members responsible for an object.
diff --git a/tooz/tests/__init__.py b/tooz/tests/__init__.py
index 505ef5f..b7acfa1 100644
--- a/tooz/tests/__init__.py
+++ b/tooz/tests/__init__.py
@@ -19,7 +19,6 @@ import os
 
 import fixtures
 from oslo_utils import uuidutils
-import six
 from testtools import testcase
 
 import tooz
@@ -49,8 +48,7 @@ class SkipNotImplementedMeta(type):
         return type.__new__(cls, name, bases, local)
 
 
-@six.add_metaclass(SkipNotImplementedMeta)
-class TestWithCoordinator(testcase.TestCase):
+class TestWithCoordinator(testcase.TestCase, metaclass=SkipNotImplementedMeta):
     url = os.getenv("TOOZ_TEST_URL")
 
     def setUp(self):
diff --git a/tooz/tests/test_coordination.py b/tooz/tests/test_coordination.py
index 1153458..55f3b68 100644
--- a/tooz/tests/test_coordination.py
+++ b/tooz/tests/test_coordination.py
@@ -17,9 +17,9 @@
 import threading
 import time
 from unittest import mock
+import urllib
 
 from concurrent import futures
-from six.moves.urllib import parse
 from testtools import matchers
 from testtools import testcase
 
@@ -49,7 +49,7 @@ class TestAPI(tests.TestWithCoordinator):
         if (tooz.coordination.Characteristics.DISTRIBUTED_ACROSS_HOSTS
            not in self._coord.CHARACTERISTICS):
             self.skipTest("This driver is not distributed across hosts")
-        scheme = parse.urlparse(self.url).scheme
+        scheme = urllib.parse.urlparse(self.url).scheme
         coord = tooz.coordination.get_coordinator(
             "%s://localhost:1/f00" % scheme,
             self.member_id)
diff --git a/tooz/tests/test_partitioner.py b/tooz/tests/test_partitioner.py
index 30aeb02..39c13b6 100644
--- a/tooz/tests/test_partitioner.py
+++ b/tooz/tests/test_partitioner.py
@@ -13,7 +13,6 @@
 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #    License for the specific language governing permissions and limitations
 #    under the License.
-import six
 
 from tooz import coordination
 from tooz import tests
@@ -32,7 +31,7 @@ class TestPartitioner(tests.TestWithCoordinator):
 
     def _add_members(self, number_of_members, weight=1):
         groups = []
-        for _ in six.moves.range(number_of_members):
+        for _ in range(number_of_members):
             m = tests.get_random_uuid()
             coord = coordination.get_coordinator(self.url, m)
             coord.start()
@@ -43,7 +42,7 @@ class TestPartitioner(tests.TestWithCoordinator):
         return groups
 
     def _remove_members(self, number_of_members):
-        for _ in six.moves.range(number_of_members):
+        for _ in range(number_of_members):
             c = self._extra_coords.pop()
             c.stop()
         self._coord.run_watchers()
@@ -80,7 +79,7 @@ class TestPartitioner(tests.TestWithCoordinator):
     def test_members_of_object_and_others(self):
         p = self._coord.join_partitioned_group(self.group_id)
         self._add_members(3)
-        o = six.text_type(u"чупакабра")
+        o = str(u"чупакабра")
         m = p.members_for_object(o)
         self.assertEqual(1, len(m))
         m = m.pop()
diff --git a/tooz/tests/test_utils.py b/tooz/tests/test_utils.py
index 39f83fb..717f4fd 100644
--- a/tooz/tests/test_utils.py
+++ b/tooz/tests/test_utils.py
@@ -19,7 +19,6 @@ import os
 import tempfile
 
 import futurist
-import six
 from testtools import testcase
 
 import tooz
@@ -113,7 +112,7 @@ class TestUtilsCollapse(testcase.TestCase):
             'b': [2],
             'c': (1, 2, 3),
         }
-        c_ex = utils.collapse(ex, exclude=set(six.iterkeys(ex)))
+        c_ex = utils.collapse(ex, exclude=set(ex.keys()))
         self.assertEqual(ex, c_ex)
 
     def test_custom_selector(self):
diff --git a/tooz/utils.py b/tooz/utils.py
index 1d7b959..4d4ec27 100644
--- a/tooz/utils.py
+++ b/tooz/utils.py
@@ -24,7 +24,6 @@ import msgpack
 from oslo_serialization import msgpackutils
 from oslo_utils import encodeutils
 from oslo_utils import excutils
-import six
 
 import tooz
 
@@ -36,7 +35,7 @@ class Base64LockEncoder(object):
             self.keyspace_url += prefix
 
     def check_and_encode(self, name):
-        if not isinstance(name, (six.text_type, six.binary_type)):
+        if not isinstance(name, (str, bytes)):
             raise TypeError("Provided lock name is expected to be a string"
                             " or binary type and not %s" % type(name))
         try:
@@ -47,7 +46,7 @@ class Base64LockEncoder(object):
                              % encodeutils.exception_to_unicode(e))
 
     def encode(self, name):
-        if isinstance(name, six.text_type):
+        if isinstance(name, str):
             name = name.encode("ascii")
         enc_name = base64.urlsafe_b64encode(name)
         return self.keyspace_url + "/" + enc_name.decode("ascii")
@@ -154,7 +153,7 @@ def collapse(config, exclude=None, item_selector=operator.itemgetter(-1)):
     if exclude is None:
         exclude = set()
     collapsed = {}
-    for (k, v) in six.iteritems(config):
+    for (k, v) in config.items():
         if isinstance(v, (tuple, list)):
             if k in exclude:
                 collapsed[k] = v
@@ -168,7 +167,7 @@ def collapse(config, exclude=None, item_selector=operator.itemgetter(-1)):
 
 def to_binary(text, encoding='ascii'):
     """Return the binary representation of string (if not already binary)."""
-    if not isinstance(text, six.binary_type):
+    if not isinstance(text, bytes):
         text = text.encode(encoding)
     return text