public static RotationalStiffness NewtonMillimetersPerRadian <T>(this T value) =>
 RotationalStiffness.FromNewtonMillimetersPerRadian(Convert.ToDecimal(value));
 public void NumberToNewtonMillimetersPerRadianTest() =>
 Assert.Equal(RotationalStiffness.FromNewtonMillimetersPerRadian(2), 2.NewtonMillimetersPerRadian());