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