[Python-Dev] The type of the result of the copy() method

[Serhiy Storchaka]

The copy() methods of list, dict, bytearray, set, frozenset, 
WeakValueDictionary, WeakKeyDictionary return an instance of the base 
type containing the content of the original collection.

The copy() methods of deque, defaultdict, OrderedDict, Counter, 
ChainMap, UserDict, UserList, WeakSet, ElementTree.Element return an 
instance of the same type as the original collection.

The copy() method of mappingproxy returns a copy of the underlying 
mapping (using its copy() method).

os.environ.copy() returns a dict.

Shouldn't it be more consistent?