code: function (link) {
          if (link.type === graph.link.LinkTypes.VALUE) {
              // Links between node and list of values.
  
              if (provider.node.isTextDisplayed(link.target)) {
                  // Don't display text on link if text is displayed on target node.
                  return "";
              } else {
                  // No text is displayed on target node then the text is displayed on link.
                  return provider.node.getTextValue(link.target);
              }
  
          } else {
              var targetName = "";
              if (link.type === graph.link.LinkTypes.SEGMENT) {
                  targetName = " " + provider.node.getTextValue(link.target);
              }
              return link.label + targetName;
          }
      }
docs: Function used to return the text representation of a link.
  
  The default behavior is to return the internal relation name as text for relation links.
  And return the target node text value for links between a node and its expanded values but only if text is not displayed on value node.
  
  @param link the link to represent as text.
  @returns {string} the text representation of the link.