def build_date_regexps(yeardigits=4, expanded=False):
    '''
    Compile set of regular expressions to parse ISO dates. The expressions will
    be created only if they are not already in REGEX_CACHE.

    It is necessary to fix the number of year digits, else it is not possible
    to automatically distinguish between various ISO date formats.

    ISO 8601 allows more than 4 digit years, on prior agreement, but then a +/-
    sign is required (expanded format). To support +/- sign for 4 digit years,
    the expanded parameter needs to be set to True.
    '''
    if yeardigits != 4:
        expanded = True
    if (yeardigits, expanded) not in DATE_REGEX_CACHE:
        cache_entry = []
        # ISO 8601 expanded DATE formats allow an arbitrary number of year
        # digits with a leading +/- sign.
        if expanded:
            sign = 1
        else:
            sign = 0
        # 1. complete dates:
        #    YYYY-MM-DD or +- YYYYYY-MM-DD... extended date format
        cache_entry.append(re.compile(r"(?P<sign>[+-]){%d}(?P<year>[0-9]{%d})"
                                      r"-(?P<month>[0-9]{2})-(?P<day>[0-9]{2})"
                                      % (sign, yeardigits)))
        #    YYYYMMDD or +- YYYYYYMMDD... basic date format
        cache_entry.append(re.compile(r"(?P<sign>[+-]){%d}(?P<year>[0-9]{%d})"
                                      r"(?P<month>[0-9]{2})(?P<day>[0-9]{2})"
                                      % (sign, yeardigits)))
        # 2. complete week dates:
        #    YYYY-Www-D or +-YYYYYY-Www-D ... extended week date
        cache_entry.append(re.compile(r"(?P<sign>[+-]){%d}(?P<year>[0-9]{%d})"
                                      r"-W(?P<week>[0-9]{2})-(?P<day>[0-9]{1})"
                                      % (sign, yeardigits)))
        #    YYYYWwwD or +-YYYYYYWwwD ... basic week date
        cache_entry.append(re.compile(r"(?P<sign>[+-]){%d}(?P<year>[0-9]{%d})W"
                                      r"(?P<week>[0-9]{2})(?P<day>[0-9]{1})"
                                      % (sign, yeardigits)))
        # 3. ordinal dates:
        #    YYYY-DDD or +-YYYYYY-DDD ... extended format
        cache_entry.append(re.compile(r"(?P<sign>[+-]){%d}(?P<year>[0-9]{%d})"
                                      r"-(?P<day>[0-9]{3})"
                                      % (sign, yeardigits)))
        #    YYYYDDD or +-YYYYYYDDD ... basic format
        cache_entry.append(re.compile(r"(?P<sign>[+-]){%d}(?P<year>[0-9]{%d})"
                                      r"(?P<day>[0-9]{3})"
                                      % (sign, yeardigits)))
        # 4. week dates:
        #    YYYY-Www or +-YYYYYY-Www ... extended reduced accuracy week date
        cache_entry.append(re.compile(r"(?P<sign>[+-]){%d}(?P<year>[0-9]{%d})"
                                      r"-W(?P<week>[0-9]{2})"
                                      % (sign, yeardigits)))
        #    YYYYWww or +-YYYYYYWww ... basic reduced accuracy week date
        cache_entry.append(re.compile(r"(?P<sign>[+-]){%d}(?P<year>[0-9]{%d})W"
                                      r"(?P<week>[0-9]{2})"
                                      % (sign, yeardigits)))
        # 5. month dates:
        #    YYY-MM or +-YYYYYY-MM ... reduced accuracy specific month
        cache_entry.append(re.compile(r"(?P<sign>[+-]){%d}(?P<year>[0-9]{%d})"
                                      r"-(?P<month>[0-9]{2})"
                                      % (sign, yeardigits)))
        #    YYYMM or +-YYYYYYMM ... basic incomplete month date format
        cache_entry.append(re.compile(r"(?P<sign>[+-]){%d}(?P<year>[0-9]{%d})"
                                      r"(?P<month>[0-9]{2})"
                                      % (sign, yeardigits)))
        # 6. year dates:
        #    YYYY or +-YYYYYY ... reduced accuracy specific year
        cache_entry.append(re.compile(r"(?P<sign>[+-]){%d}(?P<year>[0-9]{%d})"
                                      % (sign, yeardigits)))
        # 7. century dates:
        #    YY or +-YYYY ... reduced accuracy specific century
        cache_entry.append(re.compile(r"(?P<sign>[+-]){%d}"
                                      r"(?P<century>[0-9]{%d})"
                                      % (sign, yeardigits - 2)))

        DATE_REGEX_CACHE[(yeardigits, expanded)] = cache_entry
    return DATE_REGEX_CACHE[(yeardigits, expanded)]

    Compile set of regular expressions to parse ISO dates. The expressions will
    be created only if they are not already in REGEX_CACHE.

    It is necessary to fix the number of year digits, else it is not possible
    to automatically distinguish between various ISO date formats.

    ISO 8601 allows more than 4 digit years, on prior agreement, but then a +/-
    sign is required (expanded format). To support +/- sign for 4 digit years,
    the expanded parameter needs to be set to True.
    
Solutions/CyberArkAudit/Data Connectors/.python_packages/lib/site-packages/isodate/isodates.py