Exception when nesting SettingTileGroup

[Merthan]

════════ Exception caught by widgets library ═══════════════════════════════════════════════════════
The following NoSuchMethodError was thrown building SettingsTileGroup(dirty, dependencies: [_InheritedTheme, _LocalizationsScope-[GlobalKey#7e5f8]]):
The getter 'iterator' was called on null.
Receiver: null
Tried calling: iterator

The relevant error-causing widget was: 
  SettingsTileGroup file:///C:/myPath/lib/screens/settings/settingsscreen.dart:82:7
When the exception was thrown, this was the stack: 
#0      Object.noSuchMethod (dart:core-patch/object_patch.dart:53:5)
#1      List.addAll (dart:core-patch/growable_array.dart:194:28)
#2      SettingsTileGroup._buildChild (package:shared_preferences_settings/src/settings_screen.dart:311:14)
#3      SettingsTileGroup.build (package:shared_preferences_settings/src/settings_screen.dart:273:14)
#4      StatelessElement.build (package:flutter/src/widgets/framework.dart:4576:28)
...

Error Reproducable

Additionally, ExpansionSettingsTile should also have properties that other tiles have, especially subtitle and checking if it's enabled is important