code: func getVal(stub shim.ChaincodeStubInterface) pb.Response {
  	args := stub.GetArgs()
  	if len(args) != 2 {
  		return shim.Error("No key specified")
  	}
  	var err error
  	var val []byte
  	if string(args[1]) == "pub" {
  		val, err = stub.GetState("pub")
  	} else if string(args[1]) == "priv" {
  		val, err = stub.GetPrivateData("col", "priv")
  	} else {
  		return shim.Error("Unknown key specified")
  	}
  	if err != nil {
  		return shim.Error(err.Error())
  	}
  
  	return shim.Success(val)
  }
docs: // getVal retrieves the value of the KVS key