<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def combine_lists_reducer( key: str, merged_list: list, component: COMPONENT ) -> list: """ Reducer function to combine the lists for the specified key into a single, flat list :param key: The key on the COMPONENT instances to operate upon :param merged_list: The accumulated list of values populated by previous calls to this reducer function :param component: The COMPONENT instance from which to append values to the merged_list :return: The updated merged_list with the values for the COMPONENT added onto it """


    merged_list.extend(getattr(component, key))
    return merged_list