This is probably a bug that was fixed sometime in Python 3x.
Testing on 3.7.1, Python gracefully errors out:

```
➜  cpython git:(bpo-32485) ✗ python issue_32485.py
Same manager, same mux
Starting test_sameProcessSameThread
Traceback (most recent call last):
  File "issue_32485.py", line 130, in <module>
    test_sameProcessSameThread(inst1, inst2, nRuns)
  File "issue_32485.py", line 48, in test_sameProcessSameThread
    run(inst1, nRuns)
  File "issue_32485.py", line 30, in run
    inst.run()
  File "issue_32485.py", line 19, in run
    if (self.d.has_key(self.key)):
  File "<string>", line 2, in has_key
  File "/home/gus/.pyenv/versions/3.7.1/lib/python3.7/multiprocessing/managers.py", line 811, in _callmethod
    raise convert_to_error(kind, result)
multiprocessing.managers.RemoteError: 
---------------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/gus/.pyenv/versions/3.7.1/lib/python3.7/multiprocessing/managers.py", line 251, in serve_client
    function = getattr(obj, methodname)
AttributeError: 'dict' object has no attribute 'has_key'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/gus/.pyenv/versions/3.7.1/lib/python3.7/multiprocessing/managers.py", line 271, in serve_client
    fallback_func = self.fallback_mapping[methodname]
KeyError: 'has_key'
---------------------------------------------------------------------------

```