code: public final void addException(final SgClass clasz) {
          if (clasz == null) {
              throw new IllegalArgumentException("The argument 'clasz' cannot be null!");
          }
          // TODO Check if any superclass is of type Exception.
          if (!exceptions.contains(clasz)) {
              exceptions.add(clasz);
          }
      }
docs: Adds an exception to the list. Does nothing if the class is already in
  the list of exceptions.
  
  @param clasz
  Exception to add.