def get_conn(self):
        """
        Returns a BigQuery PEP 249 connection object.
        """
        service = self.get_service()
        project = self._get_field('project')
        return BigQueryConnection(
            service=service,
            project_id=project,
            use_legacy_sql=self.use_legacy_sql,
            location=self.location,
            num_retries=self.num_retries
        )
Returns a BigQuery PEP 249 connection object.