동률 값의 평균 순위

from math import isfinite

def average_ranks(values):
    if type(values) not in (list, tuple) or len(values) > 1000:
        raise ValueError("values.container")
    values = tuple(values)
    if len(values) > 1000 or any(
        type(v) not in (int, float) or
        (type(v) is float and not isfinite(v)) for v in values
    ):
        raise ValueError("values.invalid")
    order = sorted(range(len(values)), key=values.__getitem__)
    result = [0.0] * len(values)
    first = 0
    while first < len(order):
        end = first + 1
        while end < len(order) and values[order[end]] == values[order[first]]:
            end += 1
        rank = (first + 1 + end) / 2
        for i in order[first:end]:
            result[i] = rank
        first = end
    return result