How to use the @cometchat-pro/chat.CometChat.UsersRequestBuilder function in @cometchat-pro/chat

fetchUserWithSearchKey(key){
    var current = this;
    let usersRequest = new CometChat.UsersRequestBuilder().setLimit(100).setSearchKeyWord(key).build();
    usersRequest.fetchNext().then(
      userList => {
        current.updateUserList(userList);
      },
      error => {
        console.log("User list fetching failed with error:", error);
      }
    );
  }

static setUserRequestBuilder(limit){
    CCManager.userRequest = new CometChat.UsersRequestBuilder().setLimit(limit).hideBlockedUsers(true).build();
  }