∀ {α : Type u} {a : α} [inst : Std.PRange.UpwardEnumerable α] [inst_1 : LE α] [inst_2 : DecidableLE α]
  {it : Std.IterM Id α}, it.internalState.next = some a → a ≤ it.internalState.upperBound → it.IsPlausibleOutput a