public TankContainsHindranceException(ITank tank, IHindrance hindrance)
     : base(String.Format(
         "Tank ({0}) contains hindrance ({1})).",
         tank, hindrance 
     ))
 {
 }
 public HindranceContainsTankException(IHindrance hindr, ITank tank)
     : base(String.Format(
         "Hindrance ({0}) contains tank ({1}).", hindr, tank
     ))
 {
 }