I have the following code:

```
class MyClass:
    def __private(self):
        print "Hey man! This is private!"

    def public(self):
        __private()
        print "I don't care if you see this!"

if __name__ == '__main__':
    x = MyClass()
    x.public()

```

However it gives me the following error: 

`NameError: global name '_MyClass__private' is not defined`

What am I doing wrong?