new_contents: from abc import ABCMeta
  
  
  class AbstractClass(object):
      __metaclass__ = ABCMeta
  
      @classmethod
      def __subclasshook__(cls, other_class):
          return super(AbstractClass, cls).__subclasshook__(other_class) and all(
                  any(x in B.__dict__ for B in other_class.__mro__) for x in cls.__abstractmethods__)
  
subject: Add abc subpackage