code: def completed_count(self):
          
          for count, child in enumerate(self.children, start=1):
              try:
                  if isinstance(child, group):
                      child.get_results()
                  else:
                      child.get_result()
              except ResultMissing:
                  return count - 1
  
          return count
docs: Returns the total number of jobs that have been completed.
          Actors that don't store results are not counted, meaning this
          may be inaccurate if all or some of your actors don't store
          results.
  
          Raises:
            RuntimeError: If your broker doesn't have a result backend
              set up.
  
          Returns:
            int: The total number of results.