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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_graph_by_id(self, network_id: int) -> BELGraph: """Get a network from the database by its identifier and converts it to a BEL graph."""

        network = self.get_network_by_id(network_id)
        log.debug('converting network [id=%d] %s to bel graph', network_id, network)
        return network.as_bel()