shell中有错误消息,但在其他情况下运行平稳

目前,我有一个程序,要求用户输入用户名和密码,并将其与数据库进行比较,以检查它们是否对应。如果他们这样做,用户被接受,如果他们不接受,他们将再次被询问。但是,当运行此操作时,代码输出错误:

 ' AttributeError: 'Login' object has no attribute 'pack''

from tkinter import *
import tkinter.messagebox as tm
import sqlite3

class Login:
    def __init__(self,master):
        self.master = master
        master.title = ("Please login.")

        self.label_1 = Label(master, text="Username")
        self.label_2 = Label(master, text="Password")
        self.entry_1 = Entry(master)
        self.entry_2 = Entry(master)

        self.label_1.grid(row=0, sticky=E)
        self.label_2.grid(row=1, sticky=E)
        self.entry_1.grid(row=0, column=1)
        self.entry_2.grid(row=1, column=1)

        self.logbtn = Button(master, text="Login", command = self._login_btn_clickked)
        self.logbtn.grid(columnspan=2)
        self.pack()

def _login_btn_clickked(self):
    print(self.entry_1.get())
    print(self.entry_2.get())

    username = (self.entry_1.get())
    password = (self.entry_2.get())

    GetDatabase(username,password)