pylint: Fix useless-object-inheritance

https://pylint.pycqa.org/en/latest/user_guide/messages/refactor/useless-object-inheritance.html:
> Used when a class inherit from object, which under python3 is
implicit, hence can be safely removed from bases.

Fixes: https://pagure.io/freeipa/issue/9278
Signed-off-by: Stanislav Levin <slev@altlinux.org>
Reviewed-By: Stanislav Levin <slev@altlinux.org>

ipapython/install/core.py

@@ -58,7 +58,7 @@ class KnobValueError(ValueError):
         self.name = name
 
 
-class PropertyBase(six.with_metaclass(util.InnerClassMeta, object)):
+class PropertyBase(metaclass=util.InnerClassMeta):
     # shut up pylint
     __outer_class__ = None
     __outer_name__ = None
@@ -227,7 +227,7 @@ def extend_knob(base, default=_missing, bases=_missing, group=_missing,
     )
 
 
-class Configurable(six.with_metaclass(abc.ABCMeta, object)):
+class Configurable(metaclass=abc.ABCMeta):
     """
     Base class of all configurables.
 
@@ -487,7 +487,7 @@ class ComponentMeta(util.InnerClassMeta, abc.ABCMeta):
     pass
 
 
-class ComponentBase(six.with_metaclass(ComponentMeta, Configurable)):
+class ComponentBase(Configurable, metaclass=ComponentMeta):
     # shut up pylint
     __outer_class__ = None
     __outer_name__ = None

ipapython/install/typing.py

@@ -4,7 +4,6 @@
 
 import weakref
 
-import six
 
 _cache = weakref.WeakValueDictionary()
 
@@ -27,7 +26,7 @@ class ListMeta(type):
         return _cache.get(key, t)
 
 
-class List(six.with_metaclass(ListMeta, list)):
+class List(list, metaclass=ListMeta):
     __parameters__ = ()
 
     def __init__(self, *_args, **_kwargs):

ipaserver/install/ipa_otptoken_import.py

@@ -186,7 +186,7 @@ def convertEncrypted(value, decryptor=None, pconv=base64.b64decode, econv=lambda
     return None
 
 
-class XMLKeyDerivation(six.with_metaclass(abc.ABCMeta, object)):
+class XMLKeyDerivation(metaclass=abc.ABCMeta):
     "Interface for XML Encryption 1.1 key derivation."
     @abc.abstractmethod
     def __init__(self, enckey):

ipatests/test_ipaserver/test_install/test_installer.py

@@ -3,8 +3,6 @@
 #
 from __future__ import absolute_import
 
-import six
-
 from abc import ABCMeta, abstractmethod
 from collections import namedtuple
 import itertools
@@ -17,7 +15,7 @@ from ipaserver.install.ipa_replica_install import ReplicaInstall
 Keyval = namedtuple('Keyval', ['option', 'value'])
 
 
-class InstallerTestBase(six.with_metaclass(ABCMeta, object)):
+class InstallerTestBase(metaclass=ABCMeta):
     OPTS_DICT = {}
 
     # don't allow creating classes with tested_cls unspecified

pylintrc

@@ -121,7 +121,6 @@ disable=
     use-list-literal,  # pylint 2.10.0 list() vs []
     unspecified-encoding,  # pylint 2.10.0, ASCII or UTF8 and platform-specific
     use-implicit-booleaness-not-comparison,  # pylint 2.12.2, weak comparison
-    useless-object-inheritance,
 
 [REPORTS]