UnboundLocalError, can't modify the parameter "where it is not associated with a value", while it's associated with its default value

i'd checked some other similar questions trying to find out what's wrong with this but they didn't help a lot as i needed to change the value in the function myself which i don't want to, and i want the user to be able to do that.

Here's the code:

import threading

def showColor(color = "Green"):
    class loading(threading.Thread):
        def __init__(self):
            threading.Thread.__init__(self)
        def run():
            c = '>'+color+'<'
            print(c)
showColor("Red")

I REALLY have no idea why is this happening... i know it's definitely because of that global, local thing but i still can't fix it if i don't give it a value right inside of the function itself too... traceback:

cannot access local variable 'color' where it is not associated with a value

But... i mean it is associated with a value right? how can i fix it?

The problem is that the class should NOT be inside the function and must be defined outside of it and INSTEAD be CALLED inside the function.

don't know how i didn't notice that i could do this instead

So it'll be like this:

import threading

class loading(threading.Thread):
    def __init__(self):
        threading.Thread.__init__(self)

    def run(color):
        c = '>'+color+'<'
        print(c)

def showColor(color="Green"):
    loading.run(color)

showColor("Red")