∀ {M : Type u_1} [inst : TopologicalSpace M] [inst_1 : Add M] [ContinuousAdd M] {α : Type u_2} {f g : α → M}
  {x : Filter α} {a b : M},
  Filter.Tendsto f x (nhds a) → Filter.Tendsto g x (nhds b) → Filter.Tendsto (fun x => f x + g x) x (nhds (a + b))