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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def parse_ns_headers(ns_headers):
 """Ad-hoc parser for Netscape protocol cookie-attributes. The old Netscape cookie format for Set-Cookie can for instance contain an unquoted "," in the expires field, so we have to use this ad-hoc parser instead of split_header_words. XXX This may not make the best possible effort to parse all the crap that Netscape Cookie headers contain. Ronald Tschalar's HTTPClient parser is probably better, so could do worse than following that if this ever gives any trouble. Currently, this is also used for parsing RFC 2109 cookies. """

    known_attrs = ("expires", "domain", "path", "secure",
                   # RFC 2109 attrs (may turn up in Netscape cookies, too)
                   "version", "port", "max-age")

    result = []
    for ns_header in ns_headers:
        pairs = []
        version_set = False
        for ii, param in enumerate(re.split(r";\s*", ns_header)):
            param = param.rstrip()
            if param == "": continue
            if "=" not in param:
                k, v = param, None
            else:
                k, v = re.split(r"\s*=\s*", param, 1)
                k = k.lstrip()
            if ii != 0:
                lc = k.lower()
                if lc in known_attrs:
                    k = lc
                if k == "version":
                    # This is an RFC 2109 cookie.
                    v = strip_quotes(v)
                    version_set = True
                if k == "expires":
                    # convert expires date to seconds since epoch
                    v = http2time(strip_quotes(v))  # None if invalid
            pairs.append((k, v))

        if pairs:
            if not version_set:
                pairs.append(("version", "0"))
            result.append(pairs)

    return result