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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 set_bytes_transferred(self, bytes_transferred):
        ''' set the number of bytes transferred - if it has changed return True '''
        _changed = False
        if bytes_transferred:
            _changed = (self._bytes_transferred != int(bytes_transferred))
            if _changed:
                self._bytes_transferred = int(bytes_transferred)
                logger.debug("(%s) BytesTransferred: %d" % (
                             self.session_id, self._bytes_transferred))
            if AsperaSession.PROGRESS_MSGS_SEND_ALL:
                return True
        return _changed