fact: Definition id_modulefun {R : ring} (M : module R) : ismodulefun (idfun M).
imports: UniMath.Algebra.Modules.Core UniMath.Algebra.Modules.Multimodules UniMath.Algebra.Monoids UniMath.Algebra.Groups UniMath.Algebra.RigsAndRings UniMath.Foundations.Preamble UniMath.MoreFoundations.Tactics