it=any
            >
            ')'
        >
        [extra_trailers=trailer*]
    >
    |
    power<
        'filter'
        trailer< '(' arglist< none='None' ',' seq=any > ')' >
        [extra_trailers=trailer*]
    >
    |
    power<
        'filter'
        args=trailer< '(' [any] ')' >
        [extra_trailers=trailer*]
    >
    z