code: public void setComment(final boolean comment) throws IllegalArgumentException {
          // Cannot have children
          if (this.children.size() > 0) {
              throw new IllegalArgumentException("Cannot mark a " + Node.class.getSimpleName()
                  + " with children as a comment");
          }
  
          // Set
          this.comment = comment;
      }
docs: Marks this {@link Node} as a comment
  
  @param comment
  Whether or not this is a comment
  @return
  @throws IllegalArgumentException
  If this node has children