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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 ipv6(value, allow_empty = False, **kwargs):
 """Validate that ``value`` is a valid IP address version 6. :param value: The value to validate. :param allow_empty: If ``True``, returns :obj:`None <python:None>` if ``value`` is empty. If ``False``, raises a :class:`EmptyValueError <validator_collection.errors.EmptyValueError>` if ``value`` is empty. Defaults to ``False``. :type allow_empty: :class:`bool <python:bool>` :returns: ``value`` / :obj:`None <python:None>` :raises EmptyValueError: if ``value`` is empty and ``allow_empty`` is ``False`` :raises InvalidIPAddressError: if ``value`` is not a valid IP version 6 address or empty with ``allow_empty`` is not set to ``True`` """

    if not value and allow_empty is False:
        raise errors.EmptyValueError('value (%s) was empty' % value)
    elif not value:
        return None

    if not isinstance(value, str):
        raise errors.InvalidIPAddressError('value (%s) is not a valid ipv6' % value)

    value = value.lower().strip()

    is_valid = IPV6_REGEX.match(value)

    if not is_valid:
        raise errors.InvalidIPAddressError('value (%s) is not a valid ipv6' % value)

    return value