code: function _handleKey(key) {
          if (_enabled && _keyMap[key]) {
              // The execute() function returns a promise because some commands are async.
              // Generally, commands decide whether they can run or not synchronously,
              // and reject immediately, so we can test for that synchronously.
              var promise = CommandManager.execute(_keyMap[key].commandID);
              return (promise.state() !== "rejected");
          }
          return false;
      }
docs: Process the keybinding for the current key.
  
  @param {string} A key-description string.
  @return {boolean} true if the key was processed, false otherwise