anchor.diff:    } catch (e) {
       print(e);
     }
  +
  +  try {
  +    // Invalid encoding
  +    await client.call(
  +      clientURI,
  +      'createClass',
  +      [],
  +      decodeCodecs: [...client.standardCodecs],
  +    );
  +  } catch (e) {
  +    print(e);
  +  }
     await s.stop();
   }
   
  
positive.code:     clientNum += 1;
      return clientNum;
    }
  }
  
negative.code: 
    MyXmlRpcHandler() : super(methods: {}) {
      methods['hello'] = hello;
      methods['createClass'] = createClass;
    }
  
    int hello(Map params) {
  