∀ (hPos : ℕ) (startPoint endPoint : Mathlib.Tactic.Widget.StringDiagram.Node)
  (atom₁ : Mathlib.Tactic.BicategoryLike.Atom₁),
  sizeOf { hPos := hPos, startPoint := startPoint, endPoint := endPoint, atom₁ := atom₁ } =
    1 + sizeOf hPos + sizeOf startPoint + sizeOf endPoint + sizeOf atom₁