code: function getFields(tweet) {
    return _.flatten(tweetLikeObjectsToCheck.map(function(tweetLikeName) {
      var tweetLike;
      if (tweetLikeName === null) {
        tweetLike = tweet;
      } else {
        tweetLike = _.get(tweet, tweetLikeName);
      }
      if (!tweetLike) return [];
      return getFieldsFromTweetLike(tweetLike);
    }));
  }
docs: Create an array of the strings at the positions in the tweet object specified by the above arrays of field names