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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 price_str(raw_price, default=_not_defined, dec_point='.'):
 """Search and clean price value. Convert raw price string presented in any localization as a valid number string with an optional decimal point. If raw price does not contain valid price value or contains more than one price value, then return default value. If default value not set, then raise ValueError. Examples: 12.007 => 12007 00012,33 => 12.33 +1 => 1 - 520.05 => -520.05 1,000,777.5 => 1000777.5 1.777.000,99 => 1777000.99 1 234 567.89 => 1234567.89 99.77.11.000,1 => 997711000.1 NIO5,242 => 5242 Not a MINUS-.45 => 45 42 \t \n => 42 => <default> :param str raw_price: string that contains price value. :param default: value that will be returned if raw price not valid. :param str dec_point: symbol that separate integer and fractional parts. :return: cleaned price string. :raise ValueError: error if raw price not valid and default value not set. """

    def _error_or_default(err_msg):
        if default == _not_defined:
            raise ValueError(err_msg)
        return default

    # check and clean
    if not isinstance(raw_price, str):
        return _error_or_default(
            'Wrong raw price type "{price_type}" '
            '(expected type "str")'.format(price_type=type(raw_price)))

    price = re.sub('\s', '', raw_price)
    cleaned_price = _CLEANED_PRICE_RE.findall(price)

    if len(cleaned_price) == 0:
        return _error_or_default(
            'Raw price value "{price}" does not contain '
            'valid price digits'.format(price=raw_price))

    if len(cleaned_price) > 1:
        return _error_or_default(
            'Raw price value "{price}" contains '
            'more than one price value'.format(price=raw_price))

    price = cleaned_price[0]

    # clean truncated decimal (e.g. 99. -> 99)
    price = price.rstrip('.,')

    # get sign
    sign = ''
    if price[0] in {'-', '+'}:
        sign, price = price[0], price[1:]
        sign = '-' if sign == '-' else ''

    # extract fractional digits
    fractional = _FRACTIONAL_PRICE_RE.match(price)
    if fractional:
        integer, fraction = fractional.groups()
    else:
        integer, fraction = price, ''

    # leave only digits in the integer part of the price
    integer = re.sub('\D', '', integer)

    # remove leading zeros (e.g. 007 -> 7, but 0.1 -> 0.1)
    integer = integer.lstrip('0')
    if integer == '':
        integer = '0'

    # construct price
    price = sign + integer
    if fraction:
        price = ''.join((price, dec_point, fraction))

    return price