How to use the @react-native-firebase/app/lib/common.pathChild function in @react-native-firebase/app

this._database,
        pathChild(this.path, id),
        Promise.resolve(this.child(id)),
      );
    }

    const pushRef = this.child(id);

    const promise = pushRef.set(value, onComplete).then(() => pushRef);

    // Prevent unhandled promise rejection if onComplete is passed
    if (onComplete) {
      promise.catch(() => {});
    }

    return new DatabaseThenableReference(this._database, pathChild(this.path, id), promise);
  }

push(value, onComplete) {
    if (!isUndefined(onComplete) && !isFunction(onComplete)) {
      throw new Error(
        "firebase.database().ref().push(_, *) 'onComplete' must be a function if provided.",
      );
    }

    const id = generateDatabaseId(this._database._serverTimeOffset);

    if (isUndefined(value) || isNull(value)) {
      return new DatabaseThenableReference(
        this._database,
        pathChild(this.path, id),
        Promise.resolve(this.child(id)),
      );
    }

    const pushRef = this.child(id);

    const promise = pushRef.set(value, onComplete).then(() => pushRef);

    // Prevent unhandled promise rejection if onComplete is passed
    if (onComplete) {
      promise.catch(() => {});
    }

    return new DatabaseThenableReference(this._database, pathChild(this.path, id), promise);
  }

child(path) {
    if (!isString(path)) {
      throw new Error("firebase.database().ref().child(*) 'path' must be a string value.");
    }
    return new DatabaseReference(this._database, pathChild(this.path, path));
  }

child(path) {
    const childPath = pathChild(this.path, path);
    return new StorageReference(this._storage, childPath);
  }