Python's variable scope:
The module corresponds to global,
The innermost layer is local,
The outer layer is nonlocal
The variable search order: inner scope ->outer layer->global->builtin
only class, def and lamda will change the scope

When reading a variable, if local does not exist, search for nonlocal, then global
When writing a variable, if nonlocal/global is not specified, a new variable is defined in the local scope
The following example is taken from Chapter 9 of the python tutorial

def scope_test():
    def do_local():
        spam = "local spam"
    def do_nonlocal():
        nonlocal spam
        spam = "nonlocal spam"
    def do_global():
        global spam
        spam = "global spam"
    spam = "test spam"
    do_local()
    print("After local assignment:", spam)
    do_nonlocal()
    print("After nonlocal assignment:", spam)
    do_global()
    print("After global assignment:", spam)

scope_test()
print("In global scope:", spam)

I have executed your code in the interpreter and PyCharm and haven’t seen the problem you mentioned. It's best to post the executed code as well. I don't see any problems just by looking at these.