以下代码实现点击“点我”按钮，弹出信息“give fower”,划线处的代码是? (    )

import tkinter as tk

import tkinter.messagebox

from tkinter import*

root=Tk()

bt=Button(root)

bt['text']='点我'

bt.pack()

def dianji(event):

tk.messagebox.showinfo('message','give flower')

bt.bind('',)

root.mainloop()