setNodes(vs, value) {
    var args = arguments;
    var self = this;
    vs.forEach(function(v) {
      if (args.length > 1) {
        self.setNode(v, value);
      } else {
        self.setNode(v);
      }
    });
    return this;
  }
Invokes setNode method for each node in names list.
Complexity: O(|names|).