The method ZZGET_NEXT_SUBVIEW_COUNT does not have a RETURNING parameter. It cannot be called in expr

When I activate the code, it shows  The method "ZZGET_NEXT_SUBVIEW_COUNT" does not person a RETURNING parameter. It cannot beryllium called successful expressions. The coding arsenic following:

    CALL METHOD uo_model_holder->add
      EXPORTING
        im_screen_view = lo_custom_view
        im_position    = uo_model_holder->zzget_next_subview_count( ).

May I cognize what is incorrect with the coding? Thanks successful advance.