Tkinter，如何从条目中做一个计算按钮？

Question

首先，我的代码必须是希腊语的(这些都是一些运输工具，如公共汽车，半卡车，汽车等)，所以我提前道歉。事情是这样的:我想让用户在条目中输入每一种车辆的数量(我的Traffic_Volume函数的变量),在他按下Calculate按钮后得到结果(条目和数字之间的计算)。

import tkinter as tk
import tkinter.messagebox

HEIGHT = 600
WIDTH = 600
root = tk.Tk()

canvas = tk.Canvas(root, height=HEIGHT, width=WIDTH)
canvas.pack()

frame = tk.Frame(root, bg="black")
frame.place(relx=0, rely=0, relheight=1, relwidth=1)

label = tk.Label(frame, text="Κυκλοφοριακός Φόρτος", fg="black")
label.place(relwidth=1.0)

label = tk.Label(frame, text="Είδος Οχήματος")
label.place(relx=0, rely=0.1)
label = tk.Label(frame, text="Λεωφορεία")
label.place(relx=0, rely=0.2, relwidth=0.15)
label = tk.Label(frame, text="Ημιφορτηγά")
label.place(relx=0, rely=0.30, relwidth=0.15)
label = tk.Label(frame, text="Φορτηγά")
label.place(relx=0, rely=0.40, relwidth=0.15)
label = tk.Label(frame, text="Συρόμενα")
label.place(relx=0, rely=0.50, relwidth=0.15)
label = tk.Label(frame, text="Άλλα")
label.place(relx=0, rely=0.60, relwidth=0.15)
label = tk.Label(frame, text="Ι.Χ.")
label.place(relx=0, rely=0.70, relwidth=0.15)

label = tk.Label(frame, text="Αριθμός Αξόνων")
label.place(relx=0.2, rely=0.1, relwidth=0.15)
label = tk.Label(frame, text="2 ή 3 άξονες")
label.place(relx=0.2, rely=0.2, relwidth=0.15)
label = tk.Label(frame, text="2 άξονες")
label.place(relx=0.2, rely=0.30, relwidth=0.15)
label = tk.Label(frame, text="3 άξονες")
label.place(relx=0.2, rely=0.40, relwidth=0.15)
label = tk.Label(frame, text="4+ άξονες")
label.place(relx=0.2, rely=0.50, relwidth=0.15)
label = tk.Label(frame, text="2 άξονες")
label.place(relx=0.2, rely=0.60, relwidth=0.15)
label = tk.Label(frame, text="N/A")
label.place(relx=0.2, rely=0.70, relwidth=0.15)

label = tk.Label(frame, text="Συντελεστής Ισοδυναμίας")
label.place(relx=0.4, rely=0.10, relwidth=0.25)
label = tk.Label(frame, text="1.30")
label.place(relx=0.45, rely=0.20, relwidth=0.15)
label = tk.Label(frame, text="0.34")
label.place(relx=0.45, rely=0.30, relwidth=0.15)
label = tk.Label(frame, text="1.50")
label.place(relx=0.45, rely=0.40, relwidth=0.15)
label = tk.Label(frame, text="3.025")
label.place(relx=0.45, rely=0.50, relwidth=0.15)
label = tk.Label(frame, text="0.026")
label.place(relx=0.45, rely=0.60, relwidth=0.15)
label = tk.Label(frame, text="0.00")
label.place(relx=0.45, rely=0.70, relwidth=0.15)

label = tk.Label(frame, text="Αριθμός οχημάτων")
label.place(relx=0.75, rely=0.10, relwidth=0.20)
entry_1 = tk.Entry(frame, bg="white")
entry_1.place(relx=0.75, rely=0.20, relwidth=0.20)
entry_2 = tk.Entry(frame, bg="white")
entry_2.place(relx=0.75, rely=0.30, relwidth=0.20)
entry_3 = tk.Entry(frame, bg="white")
entry_3.place(relx=0.75, rely=0.40, relwidth=0.20)
entry_4 = tk.Entry(frame, bg="white")
entry_4.place(relx=0.75, rely=0.50, relwidth=0.20)
entry_5 = tk.Entry(frame, bg="white")
entry_5.place(relx=0.75, rely=0.60, relwidth=0.20)
entry_6 = tk.Entry(frame, bg="white")
entry_6.place(relx=0.75, rely=0.70, relwidth=0.20)

label = tk.Label(frame, text="Ποσοστό Κυκλοφορίας στη Λωρίδα Μελέτης(ΠΚΛΜ)")
label.place(relx=0, rely=0.8)
entry_7 = tk.Entry(frame)
entry_7.place(relx=0.7, rely=0.8)

label = tk.Label(frame, text="Διάρκεια Σχεδιασμού(σε n έτη)")
label.place(relx=0, rely=0.85)
n = entry_7 = tk.Entry(frame)
n = entry_7.place(relx=0.7, rely=0.85)

label = tk.Label(frame, text="Μέση Ετήσια Αύξηση της Κυκλοφορίας(r σε δεκαδική μορφή)")
label.place(relx=0, rely=0.9)
r = entry_8 = tk.Entry(frame)
r = entry_8.place(relx=0.7, rely=0.9)


def Traffic_Volume():
    tkinter.messagebox.showinfo("Result", "Message goes here")
    float((entry_1 * 1.30 + entry_2 * 0.34 + entry_3 * 1.50 + entry_4 * 3.025 + entry_5 * 0.026 + entry_6 * 0.00) * entry_7 * 365 * ((1 - r) ** n) - 1) / r))
    return


button = tk.Button(root, text="Calculate Traffic Volume", command=Traffic_Volume)
button.pack(side="bottom")

root.mainloop()

无论如何，提前感谢，任何帮助是非常感激的。