Kivy passcode login

Question

I'm trying to make a password system with kivy, and tried coding how many tries the users have until the code does somthing but every time i input a text it goes in a loop saying i have -(loads of numbers) tries left

main code:

def on_text_validate(self, widget):
    self.text_input_str = widget.text
    print(self.text_input_str)
    passcode_input = self.text_input_str
    passcode_input = ""
    passcode = "5up9down"
    tries = 3

    while passcode_input != passcode:
        if passcode_input != passcode:
            passcode_input
            if passcode_input == passcode:
                print("well done!")
                return True
            else:
                tries -= 1
                print("you have {tries} tries left! ")
            if tries == 0:
                print("nope")

kivy file:

WidgetsExample:


<WidgetsExample>:

    cols: 5
    rows: 5

    TextInput:
        id: passcode
        multiline: False
        size_hint: None, 1
        width: "100dp"
        text: "nice"
        on_text_validate: root.on_text_validate(self)
    Label:
        text: root.text_input_str