title: Destroying tkinter screen in different class
body: <p>In my program, once my user has logged in, a new class is opened in which a function is loaded to check if the users details are correct, and then proceeds to either close the login window, display an error message, and then reload the page. And if the user logs in successfully, then the login screen closes and the program continues. However, I'm not able to close the windows which were opened in the Main class, but I can open windows in the other classes. How can I make it so that I can close the login screen in the teacher class.</p>
  
  <pre><code>class Main:
  
      def __init__(self, screen):
          self._frame = None
          self.username = StringVar()
          self.password = StringVar()
          self.var_FName = StringVar()
          self.var_SName = StringVar()
          self.var_password1 = StringVar()
          self.var_usertype = StringVar()
          self.UserID = StringVar()
  
  
  
      def Main_menu(self):
          screen.geometry("300x250")
          screen.title("Manager of stuff")
          Label(screen, text = "Login Menu", bg = "light blue", width = "300", font = ('',35),pady = 10).pack()
          Label(text = "").pack()
          Button(text = "Login", height = "2", width = "30", command = self.login).pack()
          Label(text = "").pack()
          Button(text = "Register",height = "2", width = "30", command = self.register).pack()
  
      def login(self):
          login = Toplevel(screen) #this is the screen im trying to close
          login.title("Login")
          login.geometry("500x450")
  
          Label(login, text = "Please enter your username and password below: ").pack()
          Label(login, text = "").pack()
          Label(login, text = "Username: ").pack()
          Entry(login, textvariable = self.username).pack()
          Label(login, text = "").pack()
          Label(login, text = "Password: ").pack()
          Entry(login, textvariable = self.password, show= "*").pack()
          Label(login, text = "").pack()
          Button(login, text = "Login As a Teacher", width = 20, height = 3, command = lambda : Teacher.LoginFunc(self)).pack()
          Label(login, text = "").pack()
          Button(login, text = "Login As a Student", width = 20, height = 3, command = lambda : Student.LoginFunc(self)).pack()
          Label(login, text = "").pack()
          Button(login, text = "Back", width = 30, height = 4, command = lambda : login.destroy()).pack()
          login.mainloop()
  class Teacher (Main):
    def __init__(self, screen):
      self._frame = None
  
    def LoginFunc(self):
          while True:
              with sqlite3.connect('MyComputerScience.db') as db:
                  cursor = db.cursor()
              find_user = ("SELECT * FROM users WHERE username = ? AND password = ? AND usertype = 'Teacher'")
              cursor.execute(find_user, (self.username.get(), self.password.get()))
              results = cursor.fetchall()
              if results:
                  for i in results:
                      #Label(Main.login, text = "Log-in successful!", fg = "GREEN", font = "Calibri").pack()
                      Teacher.teachmain(self)
  
              else:
                  Main.logindestroy(self, login)
                  ms.showerror("Error", "Incorrect Details")
                  Main.login(self)  
              break
  </code></pre>