∀ {ι : Type u_1} {R : Type u_3} {M : Type u_2} [inst : DecidableEq ι] [inst_1 : Semiring R] [inst_2 : AddCommMonoid M]
  [inst_3 : Module R M] (ℳ : ι → Submodule R M) [inst_4 : DirectSum.Decomposition ℳ],
  Function.RightInverse (DirectSum.decomposeAddEquiv ℳ).symm.invFun (DirectSum.decomposeAddEquiv ℳ).symm.toFun