Python 3.x 如何使用tkinter制作绘图图形应用程序GUI？

我试图制作一个基于GUI的程序，从用户那里获取一个函数并显示其图形。输入的函数是y=x之类的基本图

在运行以下代码时，我只有在输入函数后才会遇到错误（例如，我在输入框e1中输入了x）基数为10的int（）的文本无效。

我应该做哪些更改才能正确运行它

附言：我是新手！请用简单的语言。谢谢~~

from tkinter import *
from numpy import *

def graph():

    function = Entry.get(e1)
    function = int((function))
    n1 = Entry.get(e2)
    n1 = int((n1))
    n2 = Entry.get(e3)
    n2 = int((n2))

    x_cords = range(n1,n2+1)
    y_cords = [(function) for x in x_cords]


    plt.plot(x_cords,y_cords)
    plt.show()

    return 0

main_window = Tk()
main_window.title("Grapher")

l1 = Label(main_window, text="Enter your function: ").grid(row=0,column=0)
l2 = Label(main_window, text="Enter your starting range: ").grid(row=1,column=0)
l3 = Label(main_window, text="Enter your end range: ").grid(row=2,column=0)

e1 = Entry(main_window, bd = 10, relief = RIDGE)#, textvariable = function)
e1.grid(row=0,column=1)
e2 = Entry(main_window, bd = 10, relief = RIDGE)#, textvariable = n)
e2.grid(row = 1, column = 1)
e3 = Entry(main_window, bd = 10, relief = RIDGE)
e3.grid(row = 2, column = 1)

b1 = Button(main_window, text="Graph", command = graph).grid(row=3, column=1)

main_window.mainloop()