python中本地数据帧和全局数据帧之间的链接是如何实现的？

def foo():
    global_var = "Global Variable"
    local_var = "Local Variable"
    
    print(globals()['global_var'])  # 访问全局变量
    print(locals()['local_var'])    # 访问本地变量
    
    globals()['global_var'] = "Modified Global Variable"  # 修改全局变量
    locals()['local_var'] = "Modified Local Variable"      # 修改本地变量
    
    print(global_var)  # 打印修改后的全局变量
    print(local_var)   # 打印修改后的本地变量

foo()

Global Variable
Local Variable
Modified Global Variable
Local Variable