[Twisted-Python] How to get callback return value

Hi,all! On call main method, it call self.getName() in A.py, as I use callback, I can not get the return value correctly, I thought it's because the Asynchronous attribute, how should i do? B.py main: name=self.getName() A.py def getname(): def.callback(method1) def.callback(method2) def.callback(success) return self.name def success(name): self.name=name Thanks!