以下Python代码实现点击“点我”按钮，弹出信息“give flower”，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('<Button-1>', )
root.mainloop()
root
dianji
def
give flower