Groovy: dynamically change method implementation.groovy

class MyClass {

    def printAandB() {
        print "A"
        b()
    }

    def printB() {
        print "B"
    }
}

def myObject = new MyClass()
myObject.printAandB() // print -> "AB"

// change dynamically method definition
myObject.metaClass.b = {
    print "C"
}
myObject.printAandB() // print -> "AC"