code: function(memberName) {
          var parent = this.super;
          do { parent = Object.getPrototypeOf(parent); } while (!parent.hasOwnProperty(memberName));
          return parent && parent[memberName];
      }
docs: Find member on prototype chain beginning with super class.
  @param {string} memberName
  @returns {undefined|*} `undefined` if not found; value otherwise.