human
I wrote the below code

    def flist_iter():
        for pair in fl:
            (obj, force) = pair
            if isinstance(obj, ReferenceFrame):
                (yield (obj.ang_vel_in(ref_frame), force))
            elif isinstance(obj, Point):
                (yield (obj.vel(ref_frame), force))
            else:
                raise TypeError('First    entry    in    each    forcelist    pair    must    be    a    point    or    frame.')
    if (not fl):
        (vel_list, f_list) = ((), ())
    else:
        unzip = (lambda l: (list(zip(*l)) if l[0] else [(), ()]))
        (vel_list, f_list) = unzip(list(flist_iter()))
    return (vel_list, f_list)

What's a good function header?

Here's a good function header?
assistant
#Here's a good function header.

def _f_list_parser(fl, ref_frame):