def gen_function_parens_adjust(mapping_key, node):
    """If we can avoid the outer parenthesis
    of a generator function, set the node key to
    'call_generator' and the caller will do the default
    action on that. Otherwise we do nothing.
    """
    if mapping_key.kind != 'CALL_FUNCTION_1':
        return
    args_node = node[-2]
    if args_node == 'pos_arg':
        assert args_node[0] == 'expr'
        n = args_node[0][0]
        if n == 'generator_exp':
            node.kind = 'call_generator'
        pass
    return
