docs: static UserMentionEntity[] getUserMentions(JSONObject entities) throws JSONException, TwitterException {
          if (!entities.isNull("user_mentions")) {
              JSONArray userMentionsArray = entities.getJSONArray("user_mentions");
              int len = userMentionsArray.length();
              UserMentionEntity[] userMentionEntities = new UserMentionEntity[len];
              for (int i = 0; i < len; i++) {
                  userMentionEntities[i] = new UserMentionEntityJSONImpl(userMentionsArray.getJSONObject(i));
              }
              return userMentionEntities;
          } else {
              return null;
          }
      }