Getting a value from InputText in another class. kivy

I am trying to pass a value from InputText as shown below. But I always get an empty string. If I write InputText (text = 'test'), then the word test is always transmitted and not what I enter. How to get in the UserAcount class the value that I enter into InputText()

from kivy.app import App 
from kivy.uix.button import Button
from kivy.uix.widget import Widget
from kivy.uix.label import Label
from kivy.uix.gridlayout import GridLayout 
from kivy.uix.boxlayout import BoxLayout 
from kivy.uix.textinput import TextInput
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.metrics import dp

import sqlite3

conn = sqlite3.connect('diplom.sqlite', check_same_thread = False)


class EntryMenu(Screen):

    def __init__(self, **kw):
        super(EntryMenu, self).__init__(**kw)
        box = BoxLayout(padding=150,orientation='vertical')
        self.login = TextInput(text='', multiline=False)
        box.add_widget(self.login)
        self.password = TextInput(text='', multiline=False)
        box.add_widget(self.password)
        self.error = Label(text="")
        box.add_widget(self.error)
        box.add_widget(Button(text='Entry', on_press=self.buttonClicked))
        self.add_widget(box)

    def buttonClicked(self,btn):
        self.error.text=''
        with conn:
            cursor = conn.cursor()
            sql =f'''SELECT username,password
            FROM user
            WHERE username = '{self.login.text}';
            '''
            cursor.execute(sql)
            results = cursor.fetchall()
            if results:
                if self.password.text==results[0][1]:
                    set_screen('user_acount')
                elif self.password.text!=results[0][1]:
                    self.error.text = "error password"
            else:
                self.error.text = "can not search user"



class UserAcount(Screen):
    def __init__(self,login, **kw):
        super(UserAcount, self).__init__(**kw)
        box = BoxLayout(orientation='vertical')
        self.login=login
        name = Label(text=self.login)
        box.add_widget(name)
        back_button = Button(text='Exit', on_press=lambda x:
                             set_screen('menu'), size_hint_y=None, height=dp(40))   
        box.add_widget(back_button)
        self.add_widget(box)


def set_screen(name_screen):
    sm.current = name_screen


sm = ScreenManager()
sm.add_widget(EntryMenu(name='menu'))
sm.add_widget(UserAcount(EntryMenu().login.text,name='user_acount'))

class MyApp(App):
    def __init__(self, **kvargs):
        super(MyApp, self).__init__(**kvargs)

    def build(self):
        return sm


if __name__=="__main__":
    MyApp().run()

Please tell me what I'm missing. Thanks in advance

from Getting a value from InputText in another class. kivy