如何在python中从一个类中获取变量的数据到另一个类中？

class ClassA:
    def __init__(self):
        self.data = "Hello"

class ClassB:
    def __init__(self):
        self.class_a = ClassA()

    def get_data(self):
        return self.class_a.data

b = ClassB()
print(b.get_data())  # 输出：Hello

class ClassA:
    data = "Hello"

class ClassB:
    def get_data(self):
        return ClassA.data

b = ClassB()
print(b.get_data())  # 输出：Hello

class ClassA:
    data = "Hello"

class ClassB:
    @classmethod
    def get_data(cls):
        return ClassA.data

print(ClassB.get_data())  # 输出：Hello

class ClassA:
    def __init__(self):
        self.data = "Hello"

class ClassB(ClassA):
    def get_data(self):
        return self.data

b = ClassB()
print(b.get_data())  # 输出：Hello