∀ {α : Type u_1} {β : Type u_2} {γ : Type u_3} [inst : MeasurableSpace α] {μ : MeasureTheory.Measure α}
  [inst_1 : TopologicalSpace β] [inst_2 : TopologicalSpace γ] (f : α →ₘ[μ] β) (g : α →ₘ[μ] γ),
  ↑(f.pair g) =ᵐ[μ] fun x => (↑f x, ↑g x)