question: public static Supply add ( final int divisibility , final Supply s1 , final Supply s2 ) { final Supply sum = MosaicUtils . tryAdd ( divisibility , s1 , s2 ) ; if ( null == sum ) { final String message = String . format ( "cannot add %s to %s for mosaic with divisibility %d" , s1 , s2 , divisibility ) ; throw new IllegalArgumentException ( message ) ; } return sum ; }
target:  Adds supplies representing assets corresponding to a mosaic with the specified divisibility. Throws an exception if the supplies cannot be added.