∀ {F : Type u_1} {α : Type u_2} {β : Type u_3} [inst : One α] [inst_1 : DecidableEq β] [inst_2 : One β]
  [inst_3 : FunLike F α β] [inst_4 : OneHomClass F α β] (f : F),
  Finset.imageOneHom f = { toFun := Finset.image ⇑f, map_one' := ⋯ }