<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _parse_reserved_segment(self, fptr):
 """Parse valid marker segment, segment description is unknown. Parameters fptr : file object The file to parse. Returns ------- Segment The current segment. """

        offset = fptr.tell() - 2

        read_buffer = fptr.read(2)
        length, = struct.unpack('>H', read_buffer)
        if length > 0:
            data = fptr.read(length - 2)
        else:
            data = None

        segment = Segment(marker_id='0x{0:x}'.format(self._marker_id),
                          offset=offset, length=length, data=data)
        return segment