python
diff --git a/‎src/test2.py
Lines changed: 14 additions & 0 deletions b/‎src/test2.py
Lines changed: 14 additions & 0 deletions
diff --git a/‎src/typing.py
Lines changed: 6 additions & 7 deletions b/‎src/typing.py
Lines changed: 6 additions & 7 deletions
@@ -0,0 +1,14 @@
+from typing import *
+
+alpha = TypeVar('alpha')
+beta = TypeVar('beta')
+
+X = TypeVar('X')
+
+class ABTuple(Generic[alpha, beta]):
+    def __init__(self, a : alpha, b : beta):
+        self.value = (a, b)
+
+IntXTuple = ABTuple[int, X]
+IntIntTuple = IntXTuple[int]
+
@@ -1007,7 +1007,7 @@ def __new__(cls, name, bases, namespace,
                          ", ".join(str(g) for g in gvars)))
                 tvars = gvars
 
-        if extra and extra not in bases and extra.__module__ != 'builtins':
+        if extra and extra not in bases:
             bases = (extra,) + bases
         self = super().__new__(cls, name, bases, namespace, _root=True)
         self.__parameters__ = tvars
@@ -1542,7 +1542,7 @@ class ByteString(Sequence[int], extra=collections_abc.ByteString):
 ByteString.register(type(memoryview(b'')))
 
 
-class List(list, MutableSequence[T], extra=list):
+class List(MutableSequence[T], extra=list):
 
     def __new__(cls, *args, **kwds):
         if _geqv(cls, List):
@@ -1551,7 +1551,7 @@ def __new__(cls, *args, **kwds):
         return list.__new__(cls, *args, **kwds)
 
 
-class Set(set, MutableSet[T], extra=set):
+class Set(MutableSet[T], extra=set):
 
     def __new__(cls, *args, **kwds):
         if _geqv(cls, Set):
@@ -1560,7 +1560,7 @@ def __new__(cls, *args, **kwds):
         return set.__new__(cls, *args, **kwds)
 
 
-class FrozenSet(frozenset, AbstractSet[T_co], extra=frozenset):
+class FrozenSet(AbstractSet[T_co], extra=frozenset):
     __slots__ = ()
 
     def __new__(cls, *args, **kwds):
@@ -1596,16 +1596,15 @@ class ContextManager(Generic[T_co], extra=contextlib.AbstractContextManager):
     __all__.append('ContextManager')
 
 
-class Dict(dict, MutableMapping[KT, VT], extra=dict):
+class Dict(MutableMapping[KT, VT], extra=dict):
 
     def __new__(cls, *args, **kwds):
         if _geqv(cls, Dict):
             raise TypeError("Type Dict cannot be instantiated; "
                             "use dict() instead")
         return dict.__new__(cls, *args, **kwds)
 
-class DefaultDict(collections.defaultdict, MutableMapping[KT, VT],
-                  extra=collections.defaultdict):
+class DefaultDict(MutableMapping[KT, VT], extra=collections.defaultdict):
 
     def __new__(cls, *args, **kwds):
         if _geqv(cls, DefaultDict):