如何填充在类中有类的列表

class MyClass:
    def __init__(self):
        self.nested_list = [[]]

    def add_element(self, outer_index, inner_element):
        self.nested_list[outer_index].append(inner_element)

    def get_element(self, outer_index, inner_index):
        return self.nested_list[outer_index][inner_index]

my_obj = MyClass()
my_obj.add_element(0, "A")
my_obj.add_element(0, "B")
my_obj.add_element(1, "C")
my_obj.add_element(1, "D")

print(my_obj.get_element(0, 0))  # 输出: A
print(my_obj.get_element(0, 1))  # 输出: B
print(my_obj.get_element(1, 0))  # 输出: C
print(my_obj.get_element(1, 1))  # 输出: D