∀ {G : Type u_1} [inst : Group G] (G' : Subgroup G) [inst_1 : G'.Normal]
  (he : optParam (Subgroup.map (↑(MulEquiv.refl G)) G' = G') ⋯),
  QuotientGroup.congr G' G' (MulEquiv.refl G) he = MulEquiv.refl (G ⧸ G')