如何在python中将3D列表转换为2D列表？

def convert_3d_to_2d(lst_3d):
    lst_2d = []
    for i in range(len(lst_3d)):
        for j in range(len(lst_3d[i])):
            lst_2d.append(lst_3d[i][j])
    return lst_2d

# 3D列表示例
lst_3d = [[[1, 2], [3, 4]], [[5, 6], [7, 8]], [[9, 10], [11, 12]]]

# 转换为2D列表
lst_2d = convert_3d_to_2d(lst_3d)

# 打印结果
print(lst_2d)

[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10], [11, 12]]