def _broadcast(src_processor, src_atr_name, dest_processors, dest_atr_name, transform_function):
    """
    To be used exclusively by create_broadcast.
    A broadcast function gets an attribute on the src_processor and
    sets it (possibly under a different name) on dest_processors
    """
    value = getattr(src_processor, src_atr_name)
    value = transform_function(value)
    for d in dest_processors:
        setattr(d, dest_atr_name, value)