∀ {α : Type u} {β : α → Type v} [inst : BEq α] [inst_1 : Hashable α] {m₁ m₂ : Std.DHashMap.Internal.Raw₀ α β}
  [inst_2 : LawfulBEq α],
  (↑m₁).WF →
    (↑m₂).WF →
      ∀ {k : α} {fallback : β k},
        (m₁.inter m₂).getD k fallback = if m₂.contains k = true then m₁.getD k fallback else fallback