∀ {α : Type u_1} {le : α → α → Bool} {s : Batteries.PairingHeapImp.Heap α} {a : α},
  Batteries.PairingHeapImp.Heap.NodeWF le a s →
    Batteries.PairingHeapImp.Heap.WF le (Batteries.PairingHeapImp.Heap.combine le s)