docs: function(file, event) {
      var fn = function(file) {};
      for(var i = 0; i < watchList.length; i++) {
          if(watchList[i].file === file) {
              watchers[i].on(event, fn);
              watchList[i].callback[event] = fn;
              return;
          }
      }
      throw new Error(file + " was not being watched previously");
  }