Python name mangling fun

ex.py

class foo:
    __local = 10
    def local(self): return self.__local
    def test(self, bar): return self.__local, bar.__local 

class empty:
    pass
ei= empty()
ei.__local = "hello from empty"
f = foo()

print("First local:", f.local())
print("empty local:", ei.__local)
print("both:", f.test(ei))

out.text

$ python3 ex.py
First local: 10
empty local: hello from empty
Traceback (most recent call last):
  File "ex.py", line 14, in <module>
    print("both:", f.test(ei))
  File "ex.py", line 4, in test
    def test(self, bar): return self.__local, bar.__local
AttributeError: 'empty' object has no attribute '_foo__local'