Use canonical "is None" checks instead of "== None" (#358)

Author: ambv

python2/typing.py

@@ -1268,13 +1268,13 @@ def __getitem__(self, parameters):
         return super(TupleMeta, self).__getitem__(parameters)
 
     def __instancecheck__(self, obj):
-        if self.__args__ == None:
+        if self.__args__ is None:
             return isinstance(obj, tuple)
         raise TypeError("Parameterized Tuple cannot be used "
                         "with isinstance().")
 
     def __subclasscheck__(self, cls):
-        if self.__args__ == None:
+        if self.__args__ is None:
             return issubclass(cls, tuple)
         raise TypeError("Parameterized Tuple cannot be used "
                         "with issubclass().")

src/typing.py

@@ -1193,13 +1193,13 @@ def __getitem__(self, parameters):
         return super().__getitem__(parameters)
 
     def __instancecheck__(self, obj):
-        if self.__args__ == None:
+        if self.__args__ is None:
             return isinstance(obj, tuple)
         raise TypeError("Parameterized Tuple cannot be used "
                         "with isinstance().")
 
     def __subclasscheck__(self, cls):
-        if self.__args__ == None:
+        if self.__args__ is None:
             return issubclass(cls, tuple)
         raise TypeError("Parameterized Tuple cannot be used "
                         "with issubclass().")

tox.ini

@@ -16,7 +16,6 @@ ignore =
   E128,
   E129,
   E501,
-  E711,
   W503,
   # irrelevant plugins
   B3,