code: public static boolean checkSLayer(String layerName, SNode node)
    {
      //robustness
      if (layerName == null || node == null)
      {
        return false;
      }
  
      Set<SLayer> sLayers = node.getLayers();
      if (sLayers != null)
      {
        for (SLayer l : sLayers)
        {
          Collection<Label> labels = l.getLabels();
          if (labels != null)
          {
            for (Label label : labels)
            {
              if (layerName.equals(label.getValue()))
              {
                return true;
              }
            }
          }
        }
      }
  
      return false;
    }
docs: Checks a {@link SNode} if it is member of a specific {@link SLayer}.
  
  @param layerName Specifies the layername to check.
  @param node Specifies the node to check.
  @return true - it is true when the name of layername corresponds to the
  name of any label of the SNode.