Unable to open another .py file on exiting the primary .py file

Question

I have created 2 .py files. i want that once the primary file closes, the second one opens using tkinter. This is a continuation of multiple commands for a tkinter button .

The exit button functionality I have written is:-

from Backup_Server import GUI_Interface

def close_func():
    os.kill(os.getpid(), signal.SIGINT)
    GUI_Interface()
    window.destroy()
    server_socket.close()

if __name__ == "__main__":
    exit_button = Button(topFrame, text='Quit', command=close_func)

GUI_Interface is a function that I need to call after closing the existing .py file. If I put GUI_Interface as the first command for close_func(), then it really does not go back to the 2nd step and never closes the existing .py file.

And if I place GUI_Interface in the end, it just closes the existing one and never opens the function of the new .py file.

EDIT:-

Tried implementing the given solution but it just hangs both the primary and secondary Tkinter window:_

  path_to_dir = os.getcwd()
  print("path of file:;:\n", path_to_dir)
  file_name = 'Backup_Server.py'  

  def close_func():
       os.system(f'cd "{path_to_dir}"')
       os.system(f'python {file_name}')
       exit()

  exit_button = Button(topFrame, text='Quit', command=close_func)

This is what I implemented as per the solution given.

Answer 1

So basically I have been able to solve this problem by creating another thread to GUI_Interface and then closing the existing file.