code: def ipv6(value,
           allow_empty = False,
           **kwargs):
      
      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
docs: 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``