Shouldn't __metaclass__ force the use of a metaclass in Python?

Question

I\'ve been trying to learn about metaclasses in Python. I get the main idea, but I can\'t seem to activate the mechanism. As I understand it, you can specify M to be as the

Answer 1

In Python 3 (which you are using) metaclasses are specified by a keyword parameter in the class definition:

class ClassMeta(metaclass=M):
  pass

Specifying a __metaclass__ class property or global variable is old syntax from Python 2.x and not longer supported. See also "What's new in Python 3" and PEP 2115.