def connect_partial_nodirect(self, config):
        """
        Create a partially-connected genome,
        with (unless no hidden nodes) no direct input-output connections."""
        assert 0 <= config.connection_fraction <= 1
        all_connections = self.compute_full_connections(config, False)
        shuffle(all_connections)
        num_to_add = int(round(len(all_connections) * config.connection_fraction))
        for input_id, output_id in all_connections[:num_to_add]:
            connection = self.create_connection(config, input_id, output_id)
            self.connections[connection.key] = connection
Create a partially-connected genome,
        with (unless no hidden nodes) no direct input-output connections.