code: def set_gateway_direction(self, value):
          
          if value is None or not isinstance(value, str):
              raise TypeError("GatewayDirection must be set to a String")
          elif value not in Gateway.__gateway_directions_list:
              raise ValueError("GatewayDirection must be one of specified values: 'Unspecified', 'Converging', "
                               "'Diverging', 'Mixed'")
          else:
              self.__gateway_direction = value
docs: Setter for 'gateway_direction' field.
          :param value - a new value of 'gateway_direction' field.