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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 asdict(self):
 """Encode the data in this reading into a dictionary. Returns: dict: A dictionary containing the information from this reading. """


        timestamp_str = None
        if self.reading_time is not None:
            timestamp_str = self.reading_time.isoformat()

        return {
            'stream': self.stream,
            'device_timestamp': self.raw_time,
            'streamer_local_id': self.reading_id,
            'timestamp': timestamp_str,
            'value': self.value
        }