GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it
Read( "homalg.g" ); LoadPackage( "RingsForHomalg" ); HOMALG_IO.color_display := true; ZZ := HomalgRingOfIntegersInSage( ); Display( ZZ ); wmat := imat * ZZ; W := LeftPresentation( wmat );