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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 _pad_block(self):
 """Pad block with 0. Pad current block with 0. Reader will simply treat these as corrupted record and skip the block. This method is idempotent. """

    pad_length = _BLOCK_SIZE - self.__position % _BLOCK_SIZE
    if pad_length and pad_length != _BLOCK_SIZE:
      self.__writer.write('\x00' * pad_length)
      self.__position += pad_length