def METHOD_NAME(self, definition_id: str, action_key: str) -> None:
    """Add a supported action to a machine."""
    if action_key in self._machine_actions:
        if definition_id in self._supported_actions:
            if self._machine_actions[action_key] not in self._supported_actions[definition_id]:
                self._supported_actions[definition_id].append(self._machine_actions[action_key])
        else:
            self._supported_actions[definition_id] = [self._machine_actions[action_key]]
    else:
        Logger.log("w", "Unable to add %s to %s, as the action is not recognised", action_key, definition_id)