∀ {M : Type u_1} {N : Type u_2} [inst : AddZeroClass M] [inst_1 : AddZeroClass N],
  AddMonoid.Coprod.instAddZeroClass =
    { zero := AddMonoid.Coprod.instAddZeroClass._aux_1, add := AddMonoid.Coprod.instAddZeroClass._aux_3, zero_add := ⋯,
      add_zero := ⋯ }