code: def __sync(self):
      
      pad_length = _BLOCK_SIZE - self.__reader.tell() % _BLOCK_SIZE
      if pad_length and pad_length != _BLOCK_SIZE:
        data = self.__reader.read(pad_length)
        if len(data) != pad_length:
          raise EOFError('Read %d bytes instead of %d' %
                         (len(data), pad_length))
docs: Skip reader to the block boundary.