def __init__(self, trytes, chunk_size):<EOL>
super(ChunkIterator, self).__init__()<EOL>self.trytes = trytes<EOL>self.chunk_size = chunk_size<EOL>self._offset = <NUM_LIT:0><EOL>
:param trytes:
    :py:class:`TryteString` to iterate over.

:param chunk_size:
    Number of trytes per chunk.

    The final chunk will be padded if it is too short.