如何在一个python类中访问和使用另一个类中的变量

class ClassA:
    def __init__(self):
        self.variable_a = 10

class ClassB(ClassA):
    def __init__(self):
        super().__init__()
        self.variable_b = 20

    def access_variable_a(self):
        print(self.variable_a)

obj_b = ClassB()
obj_b.access_variable_a()  # 输出：10

class ClassA:
    def __init__(self):
        self.variable_a = 10

class ClassB:
    def __init__(self):
        self.variable_b = 20

    def access_variable_a(self):
        obj_a = ClassA()
        print(obj_a.variable_a)

obj_b = ClassB()
obj_b.access_variable_a()  # 输出：10

class ClassA:
    def __init__(self):
        self.variable_a = 10

class ClassB:
    def __init__(self):
        self.variable_b = 20

    def access_variable_a(self, obj_a):
        print(obj_a.variable_a)

obj_a = ClassA()
obj_b = ClassB()
obj_b.access_variable_a(obj_a)  # 输出：10