Progressbar is not moving if using inside of a class

[oldwizard1010]

example code:

from customtkinter import (CTk, CTkButton, CTkProgressBar)
class NewprojectApp:
    def __init__(self, master=None):
        # build ui
        self.ctk1 = CTk(None)
        self.ctkprogressbar1 = CTkProgressBar(self.ctk1)
        self.ctkprogressbar1.pack(side="top")
        self.ctkbutton1 = CTkButton(self.ctk1)
        self.ctkbutton1.configure(text='ctkbutton1')
        self.ctkbutton1.pack(side="top")
        self.ctkbutton1.configure(command=self.moveProgressbar)
        # Main widget
        self.mainwindow = self.ctk1
    def run(self):
        self.mainwindow.mainloop()
    def moveProgressbar(self):
        self.ctkprogressbar1.step()
        pass
if __name__ == "__main__":
    app = NewprojectApp()
    app.run()