code: def unpack_byte(self, offset):
          
          o = self._offset + offset
          try:
              return struct.unpack_from("<B", self._buf, o)[0]
          except struct.error:
              raise OverrunBufferException(o, len(self._buf))
docs: Returns a little-endian unsigned byte from the relative offset.
          Arguments:
          - `offset`: The relative offset from the start of the block.
          Throws:
          - `OverrunBufferException`