input: Write a python function to create a GUI application with tkinter that contains a textbox and a button. When the button is clicked, the text from the textbox should be printed. 
  assert app() is None
output: import tkinter as tk
  
  def app():
      def on_button_click():
          print(textbox.get())
  
      root = tk.Tk()
      root.title("Text Printer")
  
      textbox = tk.Entry(root)
      textbox.pack()
  
      button = tk.Button(root, text="Print Text", command=on_button_click)
      button.pack()
  
      root.mainloop()