code: function(_mix) {
        if(_mix.$$chain) {
          this.chain(_mix.$$chain);
        } else if(typeof _mix === 'string') {
          this.mixin($injector.get(_mix));
        } else if(isArray(_mix)) {
          this.chain(_mix);
        } else if(isFunction(_mix)) {
          _mix.call(this.dsl, $injector);
        } else {
          this.dsl.describe(_mix);
        }
      }
docs: use the builder to process a single mixin