Swift・iOSアプリで、Firebaseにアクセスできない？

Question

##やりたいこと
Apiを作って、コードを簡潔に書きたい

##問題
書き直す前：　Firebaseにアクセス成功
書き直した後：　Firebaseにアクセスできない？から、indicatorがずっと回ったままの状態になる
書き直し後のconsole: エラーなし ↓

2018-11-30 14:53:34.637882+0900 aaabbbccc[34977:1806460]  - <AppMeasurement>[I-ACS036002] Analytics screen reporting is enabled. Call +[FIRAnalytics setScreenName:setScreenClass:] to set the screen name or override the default screen class name. To disable screen reporting, set the flag FirebaseScreenReportingEnabled to NO (boolean) in the Info.plist
objc[34977]: Class AXAccessQueue is implemented in both /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/Library/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/AccessibilityUtilities.framework/AccessibilityUtilities (0x13287f780) and /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/Library/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/Accessibility.framework/Frameworks/AXHearingSupport.framework/AXHearingSupport (0x133b26888). One of the two will be used. Which one is undefined.
objc[34977]: Class AXAccessQueueTimer is implemented in both /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/Library/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/AccessibilityUtilities.framework/AccessibilityUtilities (0x13287cd50) and /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/Library/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/Accessibility.framework/Frameworks/AXHearingSupport.framework/AXHearingSupport (0x133b268d8). One of the two will be used. Which one is undefined.
2018-11-30 14:53:35.041256+0900 aaabbbccc[34977:1806372] [AXMediaCommon] Unable to look up screen scale
2018-11-30 14:53:35.041439+0900 aaabbbccc[34977:1806372] [AXMediaCommon] Unexpected physical screen orientation
2018-11-30 14:53:35.117602+0900 aaabbbccc[34977:1806372] [AXMediaCommon] Unable to look up screen scale
2018-11-30 14:53:35.126056+0900 aaabbbccc[34977:1806372] [AXMediaCommon] Unable to look up screen scale
2018-11-30 14:53:35.126208+0900 aaabbbccc[34977:1806372] [AXMediaCommon] Unexpected physical screen orientation
1----------

コンソールを見ると、書き直した後の

REF_POSTS.child("posts").observe(.childAdded, with: { (DataSnapshot) in

で、Firebaseにアクセスできていないことが原因ではないかと考えています。
書き直した前後で書き方を変えていないが、APIのファイルではうまくいきません。
しかし、解決策がわかりません。

###Runした際の画面表示
(indicatorが回ったまま止まっています。)

###コード
書き直す前

func loadPost() {
        activityIndicatorView.startAnimating()
        Database.database().reference().child("posts").observe(.childAdded, with: { (DataSnapshot) in
            if let dict = DataSnapshot.value as? [String: Any] {
                let newPost = Post.transformPostPhoto(dict: dict, key: DataSnapshot.key)
                self.fetchUser(uid: newPost.uid!, completed: {
                    self.posts.append(newPost)
                    self.activityIndicatorView.stopAnimating()
                    self.activityIndicatorView.isHidden = true
                    self.tableView.reloadData()
                })
            }
        })
    }

書き直した後

func loadPost() {
         PostApi().observePosts { (Post) in
           self.fetchUser(uid: Post.uid!, completed: {
               self.posts.append(Post)
               self.activityIndicatorView.stopAnimating()
               self.activityIndicatorView.isHidden = true
               self.tableView.reloadData()
           })
         }
    }

class PostApi {
    var REF_POSTS = Database.database().reference().child("posts")
    
    func observePosts(complition: @escaping (Post) -> Void) {
        print("1----------")
        REF_POSTS.child("posts").observe(.childAdded, with: { (DataSnapshot) in
            print("2--------")
            print(DataSnapshot.value)
            if let dict = DataSnapshot.value as? [String: Any] {
                let newPost = Post.transformPostPhoto(dict: dict, key: DataSnapshot.key)
                complition(newPost)
            }
        })
    }

すみませんが、よろしくお願いします。

##開発環境
MacOS Mojave 10.14.1
Xcode 10.0
Swift 3.0

Answer 1

    var REF_POSTS = Database.database().reference().child("posts")

    func observePosts(complition: @escaping (Post) -> Void) {
        print("1----------")
        REF_POSTS.child("posts").observe(.childAdded, with: { (DataSnapshot) in

child("posts").child("posts") になっていませんか？

Comments

[reeeeet]

解決しました!!
ありがとうございました。