code: def start(self, header=None, **kwargs):
          
          if not self.transport:
              raise ValueError(
                  "This RecipeWrapper object does not contain "
                  "a reference to a transport object."
              )
  
          if self.recipe_step:
              raise ValueError("This recipe has already been started.")
  
          for destination, payload in self.recipe["start"]:
              self._send_to_destination(destination, header, payload, kwargs)
docs: Trigger the start of a recipe, sending the defined payloads to the
          recipients set in the recipe. Any parameters to this function are
          passed to the transport send/broadcast methods.
          If the wrapped recipe has already been started then a ValueError will
          be raised.