code: def _validate_entities(self, stages):
          
          if not stages:
              raise TypeError(expected_type=Stage, actual_type=type(stages))
  
          if not isinstance(stages, list):
              stages = [stages]
  
          for value in stages:
              if not isinstance(value, Stage):
                  raise TypeError(expected_type=Stage, actual_type=type(value))
  
          return stages
docs: Purpose: Validate whether the argument 'stages' is of list of Stage objects
  
          :argument: list of Stage objects