anchor.diff:  }
   
   abstract class Options {
  +  const Options();
  +
     Map<String, String> get params => _toMap();
   
     Map<String, String> _toMap() {
  
positive.code:   /// Can throw a [PlatformException].
    Future<bool> containsKey(
        {@required String key,
        IOSOptions iOptions,
        AndroidOptions aOptions}) async {
      final String value =
          await read(key: key, iOptions: iOptions, aOptions: aOptions);
  
negative.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');
    static const IOSOptions _defaultIOSOptions = IOSOptions();
  
    /// Encrypts and saves the [key] with the given [value].
    ///
  