anchor.diff:    /// Can throw a [PlatformException].
     Future<bool> containsKey(
         {@required String key,
  -      IOSOptions iOptions,
  +      IOSOptions iOptions = _defaultIOSOptions,
         AndroidOptions aOptions}) async {
       final String value =
           await read(key: key, iOptions: iOptions, aOptions: aOptions);
  
positive.code: import 'package:flutter/services.dart';
  import 'package:meta/meta.dart';
  
  class FlutterSecureStorage {
    const FlutterSecureStorage();
  
    static const MethodChannel _channel =
        const MethodChannel('plugins.it_nomads.com/flutter_secure_storage');
  
    /// Encrypts and saves the [key] with the given [value].
    ///
  
negative.code:   /// Can throw a [PlatformException].
    Future<void> delete(
            {@required String key,
            IOSOptions iOptions = _defaultIOSOptions,
            AndroidOptions aOptions}) =>
        _channel.invokeMethod('delete', <String, dynamic>{
          'key': key,
  