我使用m trying to make a GUI calculator, a very basic one, it only has division, subtraction, addition, and multiplication. I use the Tkinter module. I make buttons, labels, and entry widgets, then display them with pack（）function, everything is going smoothly, and then I change it to use grid（）'函数来美化事物。当我测试它时，显示了以下消息
_tkinter.TclError: bad option "-row": must be -after, -anchor, -before, -expand, -fill, -in, -ipadx, -ipady, -padx, -pady, or -side
这是我的完整代码

from tkinter import *

add_sign = "+"
sub_sign = "-"
tms_sign = "x"
div_sign = ":"

root = Tk()
operation_sign_string = StringVar()
operation_sign = Label(textvariable=operation_sign_string)
inputA = Entry(bd=3)
inputB = Entry(bd=3)

def add_onclick():
    operation_sign_string.set(add_sign)

def sub_onclick():
    operation_sign_string.set(sub_sign)

def tms_onclick():
    operation_sign_string.set(tms_sign)

def div_onclick():
    operation_sign_string.set(div_sign)

add = Button(text="+", command=add_onclick)
sub = Button(text="-", command=sub_onclick)
tms = Button(text="x", command=tms_onclick)
div = Button(text=":", command=div_onclick)

add.grid(column=1, row=2)
sub.grid(column=2, row=2)
tms.grid(column=3, row=2)
div.grid(column=4, row=2)
operation_sign.grid(column=2, row=1)
inputA.grid(column=1, row=1)
inputB.pack(column=3, row=1)

root.mainloop()

我只尝试了一种方法，将属性的顺序从grid(row=1 column=1)切换为grid(column=1, row=1)，这样就将错误从_tkinter.TclError: bad option "-row": must be -after, -anchor, -before, -expand, -fill, -in, -ipadx, -ipady, -padx, -pady, or -side更改为_tkinter.TclError: bad option "-column": must be -after, -anchor, -before, -expand, -fill, -in, -ipadx, -ipady, -padx, -pady, or -side
我完全不知道为什么tkinter会吐出这个错误。