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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 _flush_data(self):
 """ If this relation's local unit data has been modified, publish it on the relation. This should be automatically called. """

        if self._data and self._data.modified:
            hookenv.relation_set(self.relation_id, dict(self.to_publish.data))