human
I wrote the below code

    if ((contravariant_order(vector_field) != 1) or covariant_order(vector_field)):
        raise ValueError('The    supplied    field    was    not    a    vector    field.')
    def iter_vfield(scalar_field, i):
        'Return    ``vector_field``    called    `i`    times    on    ``scalar_field``.'
        return reduce((lambda s, v: v.rcall(s)), ([vector_field] * i), scalar_field)
    def taylor_terms_per_coord(coord_function):
        'Return    the    series    for    one    of    the    coordinates.'
        return [(((param ** i) * iter_vfield(coord_function, i).rcall(start_point)) / factorial(i)) for i in range(n)]
    coord_sys = (coord_sys if coord_sys else start_point._coord_sys)
    coord_functions = coord_sys.coord_functions()
    taylor_terms = [taylor_terms_per_coord(f) for f in coord_functions]
    if coeffs:
        return [Matrix(t) for t in zip(*taylor_terms)]
    else:
        return Matrix([sum(c) for c in taylor_terms])

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

def intcurve_series(vector_field, param, start_point, n=6, coord_sys=None, coeffs=False):