code: def add_metaclass(metaclass):
      
      vars_to_skip = ('__dict__', '__weakref__')
  
      def wrapper(cls):
          copied_dict = {
              key: value
              for key, value in cls.__dict__.items()
              if key not in vars_to_skip
          }
          return metaclass(cls.__name__, cls.__bases__, copied_dict)
      return wrapper
docs: Class decorator for creating a class with a metaclass.
  
      Adapted from the six project:
  
      https://pythonhosted.org/six/