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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def __sync(self):
 """Skip reader to the block boundary."""

    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))