∀ {R : Type u_2} {E : Type u_1} [inst : Semiring R] [inst_1 : InvolutiveStar R] [inst_2 : AddCommMonoid E]
  [inst_3 : Module R E] [inst_4 : StarAddMonoid E] [inst_5 : StarModule R E] (f : WithConv (Module.End R E)ˣ),
  (star (WithConv.toConv ↑f.ofConv)).ofConv * (star (WithConv.toConv ↑f.ofConv⁻¹)).ofConv = 1