old_contents: from multiprocessing import process
  
  
  class Actor(process.BaseProcess):
      def __init__(self):
          super(Actor, self).__init__()
          self._inbox = list()
  
      def send(self, value):
          self._inbox.append(value)
  
      @property
      def inbox(self):
          return self._inbox
  
new_contents: from multiprocessing import Process
  
  
  class Actor(Process):
      def __init__(self):
          super(Actor, self).__init__()
          self._inbox = list()
  
      def send(self, value):
          self._inbox.append(value)
  
      @property
      def inbox(self):
          return self._inbox
  
subject: Change BaseProcess to Process as a parent class for Actor