@Override
 public <V> V accept(final FixedIncomeFutureInstrumentDefinitionVisitor<?, V> visitor) {
   return visitor.visitBondFutureDefinition(this);
 }
 @Override
 public <U, V> V accept(
     final FixedIncomeFutureInstrumentDefinitionVisitor<U, V> visitor, final U data) {
   return visitor.visitBondFutureDefinition(this, data);
 }