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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(self, key):
        '''
        Get a value for a given key

        :param key: entry's key
        :return: corresponding value
        '''
        if key in self._data_fields:
            return self._data_fields[key]
        if key in self._sub_reports:
            return self._sub_reports[key]
        return None