GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it
Read( "homalg.g" ); W := M; II_E := GrothendieckSpectralSequence( RightDualizingFunctor( R ), LeftDualizingFunctor( R ), W ); filt := FiltrationBySpectralSequence( II_E ); m := IsomorphismOfFiltration( filt );