คุณสมบัติของโปรแกรม · ความตรงกันของค่า Content-Length

import re

def agreed_content_length(fields):
    if type(fields) is not list or not 1 <= len(fields) <= 16:
        raise ValueError("length.fields")
    result = None
    for field in fields:
        if type(field) is not str or len(field) > 128:
            raise ValueError("length.field")
        for item in field.split(","):
            token = item.strip(" \t")
            if re.fullmatch(r"[0-9]+", token) is None:
                raise ValueError("length.digits")
            value = int(token)
            if value > 2147483647 or (result is not None and value != result):
                raise ValueError("length.agreement")
            result = value
    return result