code: function (args, callback) {
              let child = this
                  .runProtractor(args)
                  .on('exit', function (code) {
                      if (child) {
                          child.kill();
                      }
  
                      if (callback) {
                          callback(code);
                      }
                  });
          }
docs: Execute the protractor engine
  
  @method
  @static
  @param {string[]} args
  @param {Function} callback