我想添加错误页面时，表单没有填写在python tkinter中

import tkinter as tk

root = tk.Tk()
root.title("错误页面")

form = tk.Frame(root)
form.pack()

# 添加标签和输入框
label = tk.Label(form, text="请输入内容：")
label.pack()

entry = tk.Entry(form)
entry.pack()

error_label = tk.Label(root, text="请填写表单内容！", fg="red")
error_label.pack()
error_label.grid_remove()  # 隐藏错误提示

def submit_form():
    if entry.get() == "":
        error_label.grid()  # 显示错误提示
    else:
        # 执行表单提交操作
        # ...

submit_button = tk.Button(root, text="提交", command=submit_form)
submit_button.pack()

root.mainloop()