def _ConvertValueBinaryDataToUBInt64(self, value):
    """Converts a binary data value into an integer.

    Args:
      value (bytes): binary data value containing an unsigned 64-bit big-endian
          integer.

    Returns:
      int: integer representation of binary data value or None if value is
          not set.

    Raises:
      ParseError: if the integer value cannot be parsed.
    """
    if not value:
      return None

    integer_map = self._GetDataTypeMap('uint64be')

    try:
      return self._ReadStructureFromByteStream(value, 0, integer_map)
    except (ValueError, errors.ParseError) as exception:
      raise errors.ParseError(
          'Unable to parse integer value with error: {0!s}'.format(
              exception))