Simple login example

#PY3
import subprocess
import hashlib
import base64
from urllib.request import urlopen
import tkinter as tk
from tkinter import messagebox
def encode_with_hwid(string,hwid_):
    sha = (hashlib.sha512(bytes(str(string).encode('utf-8') + hwid_.encode('utf-8'))).hexdigest())
    return (base64.b64encode(sha.encode('utf-8'))).decode() # SHA 512 Encryption
def get_hwid():
    return str(subprocess.check_output('wmic csproduct get uuid')).split('\\r\\n')[1].strip('\\r').strip() # WINDOWS SUPPORTED ONLY! so if lin systems are different
def checkLogin(key):
    HWID = get_hwid()
    ENCODED = (encode_with_hwid(key,HWID))
    if ENCODED in db:
        messagebox.showinfo("Welcome!","You've been logged in successfully!")
    else:
        messagebox.showinfo("Incorrect information!","Either you've inputed the wrong key or it doesn't exist.", icon = 'error')
    return
# Getting database...
db = urlopen("https://pastebin.com/raw/j9tEQPt0").read().decode().split()

# Setting up the GUI
class loginPage(tk.Frame):
    def __init__(self, master = None):
        tk.Frame.__init__(self,master)
        self.page_settings()
        self.title()
        self.key_label()
        self.key_entry()
        self.login_button()
        self.master.mainloop()
    def page_settings(self):
        self.master.geometry("400x200") # W x H
        self.master.title("Login Page - Example")
        self.master.resizable(width = False, height = False)
        self.master.attributes('-topmost', True)
        self.master.configure(background = 'black')
    def title(self):
        T = tk.Label(self.master, text = "Login Page")
        T.configure(background = 'black', foreground = 'green', font = ('Arial Black',20,'bold','underline'))
        T.place(x = 200, y = 20, anchor = 'center')
    def key_label(self):
        username_field = tk.Label(self.master, text = "Key")
        username_field.configure(background = 'black', foreground = 'white', font = ('Arial Black',12,'bold'))
        username_field.place(x = 0, y = 50)
        required_mark = tk.Label(self.master, text = "*")
        required_mark.configure(background = 'black', foreground = 'red', font = ('Arial Black',12,'bold'))
        required_mark.place(x = 40, y = 50)
    def key_entry(self):
        global entry
        entry = tk.Entry(self.master)
        entry.configure(background = 'black', foreground = 'white', font = ('Arial Black',12,'bold'))
        entry.place(x = 0, y = 80)
    def login_button(self):
        LOGIN_B = tk.Button(self.master, text = "Sign in", command = lambda:checkLogin(entry.get()))
        LOGIN_B.configure(background = 'black', foreground = 'red', font = ('Arial Black',12,'bold'), borderwidth = 0)
        LOGIN_B.place(x = 200, y = 170, anchor = 'center', width = 180)

mainPage = tk.Tk()
loginPage(master = mainPage)