<s>[INST] import tkinter as tk

class Application(tk.Tk):
    def __init__(self):
        super().__init__()
        self.title("Password Manager")
        self.geometry("300x200")

app = Application()
app.mainloop()

if __name__ == "__main__":
    app.run()
```

This is a simple Tkinter application. I'm trying to start the main event loop using `app.run()`, but I get an error saying `AttributeError: 'Application' object has no attribute 'run'`. 

Why do I get this error and how can I fix it?[/INST]