Put Keychain related methods to separate class

passKit/Helpers/AppKeychain.swift

@@ -0,0 +1,40 @@
+//
+//  AppKeychain.swift
+//  passKit
+//
+//  Created by Danny Moesch on 25.06.19.
+//  Copyright © 2019 Bob Sun. All rights reserved.
+//
+
+import KeychainAccess
+
+public class AppKeychain {
+    
+    private static let keychain = Keychain(service: Globals.bundleIdentifier, accessGroup: Globals.groupIdentifier)
+        .accessibility(.whenUnlockedThisDeviceOnly)
+        .synchronizable(false)
+
+    public static func add(data: Data, for key: String) {
+        keychain[data: key] = data
+    }
+
+    public static func add(string: String, for key: String) {
+        keychain[key] = string
+    }
+
+    public static func get(for key: String) -> Data? {
+        return try? keychain.getData(key)
+    }
+
+    public static func get(for key: String) -> String? {
+        return try? keychain.getString(key)
+    }
+
+    public static func removeContent(for key: String) {
+        try? keychain.remove(key)
+    }
+
+    public static func removeAllContent() {
+        try? keychain.removeAll()
+    }
+}