input: Write a python function to create a tkinter window with a label that updates every second to show the current time.
  assert create_time_window() is None
output: import tkinter as tk
  import time
  
  def update_time(label):
      current_time = time.strftime('%H:%M:%S')
      label.config(text=current_time)
      label.after(1000, update_time, label)
  
  def create_time_window():
      root = tk.Tk()
      root.title("Current Time")
      time_label = tk.Label(root, font=('Helvetica', 48), fg='black')
      time_label.pack()
      update_time(time_label)
      root.mainloop()