∀ {M : Type u_1} {α : Type u_2} [inst : Group M] [inst_1 : MulAction M α] {s t : Set α} {g : M} (hg : g • t = s),
  SubMulAction.conjMap_ofFixingSubgroup hg =
    {
      toFun := fun x =>
        match x with
        | ⟨x, hx⟩ => ⟨g • x, ⋯⟩,
      map_smul' := ⋯ }