Cleanup inspect

* use isinstance(..)  instead of type(..)
* use  '.. not in ..'  instead of 'not .. in ..	'

Lib/inspect.py

@@ -993,7 +993,7 @@ def getclasstree(classes, unique=False):
     for c in classes:
         if c.__bases__:
             for parent in c.__bases__:
-                if not parent in children:
+                if parent not in children:
                     children[parent] = []
                 if c not in children[parent]:
                     children[parent].append(c)
@@ -1538,7 +1538,7 @@ def _shadowed_dict(klass):
         except KeyError:
             pass
         else:
-            if not (type(class_dict) is types.GetSetDescriptorType and
+            if not (isinstance(class_dict, types.GetSetDescriptorType) and
                     class_dict.__name__ == "__dict__" and
                     class_dict.__objclass__ is entry):
                 return class_dict
@@ -1560,7 +1560,7 @@ def getattr_static(obj, attr, default=_sentinel):
         klass = type(obj)
         dict_attr = _shadowed_dict(klass)
         if (dict_attr is _sentinel or
-            type(dict_attr) is types.MemberDescriptorType):
+            isinstance(dict_attr, types.MemberDescriptorType)):
             instance_result = _check_instance(obj, attr)
     else:
         klass = obj
@@ -1975,7 +1975,7 @@ def _signature_fromstr(cls, obj, s, skip_bound_arg=True):
 
     def parse_name(node):
         assert isinstance(node, ast.arg)
-        if node.annotation != None:
+        if node.annotation is not None:
             raise ValueError("Annotations are not currently supported")
         return node.arg