code: function( path, pathString ) {
              if (path.hidden && pathString.charAt(0) !== "_") { // path will be shown, so show it
                  path.show();
                  path.hidden = false;
              }
  
              // See: http://dmitrybaranovskiy.github.io/raphael/reference.html#Element.animate
              path.animate(
                  {
                      path: pathString.charAt(0) === "_"?
                          pathString.substring(1):
                          pathString // remove the "_" prefix if it exists
                  },
                  this.CONFIG.animation.connectorsSpeed,
                  this.CONFIG.animation.connectorsAnimation,
                  function() {
                      if ( pathString.charAt(0) === "_" ) { // animation is hiding the path, hide it at the and of animation
                          path.hide();
                          path.hidden = true;
                      }
                  }
              );
              return this;
          }
docs: This method relied on receiving a valid Raphael Paper.path.
  See: http://dmitrybaranovskiy.github.io/raphael/reference.html#Paper.path
  A pathString is typically in the format of "M10,20L30,40"
  @param path
  @param {string} pathString
  @returns {Tree}