code: function (less, pluginManager) {
          var functions = this.getInstance(less);
          var registry = less.functions.functionRegistry;
  
          for (var name in functions) {
              // only inject if not exsits
              if (functions.hasOwnProperty(name) && !registry.get(name)) {
                  registry.add(name, functions[name]);
              }
          }
      }
docs: Installation
  @param {Object} less the less.js instance
  @param {Object} pluginManager less.js plugin manager instance