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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 iter_chunks(self):
 """ Generate a |_Chunk| subclass instance for each chunk in this parser's PNG stream, in the order encountered in the stream. """

        for chunk_type, offset in self._iter_chunk_offsets():
            chunk = _ChunkFactory(chunk_type, self._stream_rdr, offset)
            yield chunk