python清空tree.insert()

import tkinter
from tkinter import ttk  # 导入内部包

li = ['王记', '', '男']
root = tkinter.Tk()
root.title('测试')
tree = ttk.Treeview(root, columns=['', '', ''], show='headings')
tree.column('', width=100, anchor='center')
tree.column('', width=100, anchor='center')
tree.column('', width=100, anchor='center')
tree.heading('', text='姓名')
tree.heading('', text='学号')
tree.heading('', text='性别')
tree.insert('', 'end', values=li)
tree.grid()

def delButton(tree):
    x = tree.get_children()
    for item in x:
        tree.delete(item)

delButton(tree)

root.mainloop()