class MainScreen(tk.Frame):

def __init__(self, parent, controller):
    tk.Frame.__init__(self,parent)
    label = ttk.Label(self, text="Main Screen", font=LARGE_FONT)
    label.pack(pady=10,padx=10)

    logo = ImageTk.PhotoImage(Image.open('logo.png'))

    button = ttk.Button(self, text="Teacher",
                        command=lambda: controller.show_frame(Teacher))
    button.pack()

    button2 = ttk.Button(self, text="Student",
                        command=lambda: controller.show_frame(Student))
    button2.pack()


class Teacher(tk.Frame):

def __init__(self, parent, controller):
    tk.Frame.__init__(self, parent)
    label = ttk.Label(self, text="Teacher Login", font=LARGE_FONT)
    label.pack(pady=10,padx=10)

    logo = ImageTk.PhotoImage(Image.open('logo.png'))

    button1 = ttk.Button(self, text="Login",
                        command=lambda: controller.show_frame(main.login))
    button1.pack()


    button1 = ttk.Button(self, text="Home",
                        command=lambda: controller.show_frame(MainScreen))
    button1.pack()

#main Class
 class main:
 def __init__(self,master):
#Login Function
def login(self):
    #Establish Connection
    with sqlite3.connect('admin.db') as db:
        c = db.cursor()

    #Find user If there is any take proper action
    find_user = ('SELECT * FROM user WHERE username = ? and password = ?')
    c.execute(find_user,[(self.username.get()),(self.password.get())])
    result = c.fetchall()
    if result:
        self.logf.pack_forget()
        self.head['text'] = self.username.get() + 'n Loged In'
        self.head['pady'] = 150
    else:
        ms.showerror('Oops!','Username Not Found.')