code: def unpack_dosdate(self, offset):
          
          try:
              o = self._offset + offset
              return dosdate(self._buf[o:o + 2], self._buf[o + 2:o + 4])
          except struct.error:
              raise OverrunBufferException(o, len(self._buf))
docs: Returns a datetime from the DOSDATE and DOSTIME starting at
          the relative offset.
          Arguments:
          - `offset`: The relative offset from the start of the block.
          Throws:
          - `OverrunBufferException`