code: public final void add(ObservableDoubleValue dependency) {
          requireNonNull(dependency, "Parameter 'dependency' is null");
  
          if (!dependencies.contains(dependency)) {
  
              dependencies.add(dependency);
              bind(dependency);
              invalidate();
  
          } else {
              LOGGER.warn("Dependency already included: " + dependency + ", Skipping.");
          }
      }
docs: Bind the new (not previously bound) dependency.
  @param dependency The dependency to be bound