parent.name在parent实例化之前不存在，所以child没法访问到parent.name
有两种方法

class parent:  
    name = 'parent'  
  
    def getName(self):  
        print(self.name)

    class child:
        def getName(self):
            return parent.name
  
  
if __name__ == '__main__':  
    child =  parent.child()  
    child.getName()

或者先实例化parent然后传参进去

class parent:  
    def __init__(self):  
        self.name = 'parent'  

  
    def getName(self):  
        print(self.name)

    class child:
        def __init__(self,parent):
            self.parent = parent

        def getName(self):
            return self.parent.name
  
  
if __name__ == '__main__':  
    parent = parent()
    child =  parent.child(parent)  
    child.getName()