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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 get_datastream_names(self):
        '''Returns a set with the datastream names. If there is no datastream,
        returns None
        '''
        ads_names = set()

        for stream in self.data_streams:
            ads_names.add(stream.name)

        if len(ads_names):
            return ads_names
        else:
            return None