Gradle/groovy:从自定义类调用“global”函数

我对groovy/gradle不熟悉 据我所知,Gealth/Groovy与Java兼容。

我在“build.gradle”文件中编写了以下Gradle(没有任何任务):

def myFun = {->"Hello World"}

class MyClass {
    String getLabel() {
        return ""+ myFun();
        }
    }

System.err.println(new MyClass().getLabel());

在哪里上课 MyClass 调用“全局”(?)功能 myFun .

打电话 gradle --tasks 产生以下错误:

FAILURE: Build failed with an exception.

* Where:
Build file 'build.gradle' line: 6

* What went wrong:
A problem occurred evaluating root project 'tmp'.
> No signature of method: MyClass.myFun() is applicable for argument types: () values: []
  Possible solutions: find(), find(groovy.lang.Closure), wait(), any(), every(), dump()

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 2.671 secs

我怎么上这个课 类名 “查看”功能 MyFun ?

谢谢您。