code: double getPaddingValue(double defaultPadding) {
          double padding = model.get(RendererModel.Padding.class);
          if (padding == AUTOMATIC)
              padding = defaultPadding;
          return padding;
      }
docs: Access the specified padding value or fallback to a provided
  default.
  
  @param defaultPadding default value if the parameter is 'automatic'
  @return padding