Whys is asterisk and random variable necessary in these functions?

[rrowhe4d]

In this basic Python Tkinter code, I'm trying to bind certain functions to trigger upon either a UI button press or a keyboard key press.

import tkinter as tk
from tkinter import ttk

main_window = tk.Tk()
main_window.title('Test UI')

# Change text with "Enter" then flush
def changeTextEnter():
    text_label.configure(text=entry_bar.get())
    entry_bar.delete(0, tk.END)

# Close program key function
def quitApp():
    main_window.destroy()

# Enter Button
enter_button = ttk.Button(text='Enter', command=changeTextEnter)
enter_button.grid(row=0, column=0)

# Entry bar
entry_bar = ttk.Entry(width=30)
entry_bar.grid(row=0, column=1)

# Quit Button
quit_button = ttk.Button(text='Quit', command=main_window.destroy)
quit_button.grid(row=0, column=2)

# Text label
text_label = ttk.Label(text='TEST TEXT GOES HERE')
text_label.grid(row=1, column=0, columnspan=2)

# Bind enter key
main_window.bind('<Return>', changeTextEnter)
# Bind quit key
main_window.bind('<Escape>', quitApp)

main_window.mainloop()

After a while of trial and error, it seems to work the way I want if I add an *randomVariable in the declarations of def changeTextEnter(*randomVariable): and def quitApp(*randomVariable):
I get that one asterisk lets the function take an unknown number of arguments, and a double asterisk acts as a dictionary with key values.

My questions are:

1. Why do I need a parameter in those functions at all?
   
2. How does the variable *randomVariable get used, since it seems like I'm not actually using/ assigning anything to randomVariable anywhere within the function.
   
3. Why does the function not work as intended without the asterisk before the variable?