      WHERE ST_%s($1, the_geom)
      ', geom_colname, geom_colname, geoid_colname, target_table, overlap_type)
   USING geom;
+  RETURN;
 
 END;
 $$ LANGUAGE plpgsql;

                          time_span,
                          overlap_type
                        );

END;
$$ LANGUAGE plpgsql;

                        circle_boundary,
                        boundary_id,
                        time_span);
  RETURN;
END;
$$ LANGUAGE plpgsql;

