∀ {ι : Type u_7} [inst : Finite ι] {X : ι → Type u_8} {Y : ι → Type u_9} [inst_1 : (i : ι) → TopologicalSpace (X i)]
  [inst_2 : (i : ι) → TopologicalSpace (Y i)] (ei : (i : ι) → OpenPartialHomeomorph (X i) (Y i)),
  (OpenPartialHomeomorph.pi ei).source = Set.univ.pi fun i => (ei i).source