code: def get_id(id_or_obj):
      
      if isinstance(id_or_obj, six.string_types + (int,)):
          # It's an ID
          return id_or_obj
      try:
          return id_or_obj.id
      except AttributeError:
          return id_or_obj
docs: Returns the 'id' attribute of 'id_or_obj' if present; if not,
      returns 'id_or_obj'.