Infinite recursion in pickling dynamically generated classes

[robertwb]

Consider

def createB():       
     class B(object):
       def __init__(self):
         super(B, self).__init__()
     return B

Now dill.dumps(createB()) fails with an infinite loop of

T2: <class '__main__.B'>
D2: <dict object at 0x10ef5e050>
F1: <function __init__ at 0x10f075aa0>
D1: <dict object at 0x10e7ac050>
# D1
Ce: <cell at 0x10f013e88: type object at 0x7ff6a1d7cdb0>
T2: <class '__main__.B'>
...

[mmckerns]

I think this is very similar to #56, but I guess it looks like it's not a duplicate. Either way, the same error is thrown. Basically, dill can't find class B in the top-level namespace.