Python name mangling

mangle.py

>>> class A:
...    def __init__(self, __foo):
...        print(__foo)
...
>>> dis.dis(A.__init__)
  3           0 LOAD_GLOBAL              0 (print)
              2 LOAD_FAST                1 (_A__foo)
              4 CALL_FUNCTION            1
              6 POP_TOP
              8 LOAD_CONST               0 (None)
             10 RETURN_VALUE