title: 'super' object has no attribute '__getattr__' when I try to access screen ids
body: <p>Since two days I have tried to solve this problem. I try almost everything. I checked my ids 10 times whether or not they are string. They are not!! I put clock.schedule_one method for delaying initializations but program does not define ids in kv file. Here is the code;</p>
  <pre><code>from kivymd.theming import ThemeManager
  from kivymd.app import MDApp
  from kivy.lang import Builder
  from kivy.core.window import Window
  from kivy.uix.screenmanager import ScreenManager, Screen
  from kivy.uix.floatlayout import FloatLayout
  from kivymd.uix.tab import MDTabsBase
  from kivy.clock import Clock
  from kivy.properties import ObjectProperty
  from kivy.app import App
  Window.size = (300 , 400)
  
  
  class Screen1(Screen):
      pass
  class Screen2(Screen):
      pass
  class Manager(ScreenManager):
      pass
  
  
  Builder.load_string(&quot;&quot;&quot;
  
  &lt;Manager&gt;:
    
      Screen1:
          
      Screen2:
          
  &lt;Screen1&gt;:
      name:&quot;scr1&quot;
      
      BoxLayout:
          
          orientation: 'vertical'
          MDToolbar:
              
              title:&quot;ahmet&quot;
          MDTabs:
              
              tab_display_mode: &quot;text&quot;
              on_tab_switch:app._press
              
              
              MDTabsBase:
                  id:hasta
                  text: &quot;hasta&quot;
                  
                     
              MDTabsBase:
                  id:doktor
                  text: &quot;doktor&quot;
  
              
  
      FloatLayout:
          
                     
          MDRoundFlatIconButton:
              on_press:app._doThis
              text:&quot;submit&quot;
              pos_hint:{&quot;x&quot;:0.3,&quot;top&quot;:0.7}
              
      FloatLayout:
          orientation: 'vertical'
          MDTextFieldRound:
              id:email
              icon_left: &quot;email&quot;
              hint_text: &quot;email&quot;
              pos_hint:{&quot;x&quot;:0.35,&quot;top&quot;:0.5}
              size_hint:0.3,0.05
          MDTextFieldRound:
              id:password
              icon_left: &quot;password&quot;
              hint_text: &quot;password&quot;
              pos_hint:{&quot;x&quot;:0.35,&quot;top&quot;:0.4}
              size_hint:0.3,0.05
          MDLabel:
              multinline:True
              text:
                  &quot;label&quot;
              pos_hint:{&quot;x&quot;:0.2,&quot;top&quot;:0.35}
              size_hint:0.6,0.3
              font_style:&quot;H6&quot;
              font_size:15
              theme_text_color: &quot;Custom&quot;
              text_color: 0, 0, 1, 1
          
  
  &lt;Screen2&gt;:
      name:&quot;scr2&quot;
      
      BoxLayout:
          
          orientation: 'vertical'
          MDToolbar:
              text:&quot;ahmet&quot;
          MDTabs:
              
              on_tab_switch:app._press
              MDTabsBase:
                  id:hasta
                  text: &quot;hasta&quot;
                  
                     
              MDTabsBase:
                  id:doktor
                  text: &quot;doktor&quot;
      FloatLayout:
          orientation: 'horizontal'
          MDRoundFlatIconButton:
              on_press:app._doThis
              text:&quot;submit&quot;
              pos_hint:{&quot;x&quot;:0.3,&quot;top&quot;:0.7}
              
          
             
      FloatLayout:
          orientation: 'vertical'
          MDTextFieldRound:
              id:email
              icon_left: &quot;email&quot;
              hint_text: &quot;email&quot;
              pos_hint:{&quot;x&quot;:0.35,&quot;top&quot;:0.5}
              size_hint:0.3,0.05
          MDTextFieldRound:
              id:password
              icon_left: &quot;password&quot;
              hint_text: &quot;password&quot;
              pos_hint:{&quot;x&quot;:0.35,&quot;top&quot;:0.4}
              size_hint:0.3,0.05
          MDLabel:
              multiline:True
              text:
                  &quot;label&quot;
              pos_hint:{&quot;x&quot;:0.2,&quot;top&quot;:0.35}
              size_hint:0.6,0.3
              font_style:&quot;H6&quot;
              font_size:15   
              theme_text_color: &quot;Custom&quot;
              text_color: 0, 0, 1, 1            
  &quot;&quot;&quot;)
  
  
  
  
  class DemoApp(MDApp):
      
      def build(self):
          Clock.schedule_once(self._press,2)
          Clock.schedule_once(self._doThis,2)
          return Manager()
      
      def _press(self,*dt):
          self.root.ids.hasta.text
          
       
      def _doThis(self,*dt):
          self.root.ids.hasta.text
          
     
  DemoApp().run()
  </code></pre>
  <p>And here is the error message;</p>
  <pre><code>KeyError: 'hasta'
  
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
  
    File &quot;C:\Users\Melikşah GÜRCÜ\Desktop\md.py&quot;, line 162, in &lt;module&gt;
      DemoApp().run()
  
    File &quot;C:\python\lib\site-packages\kivy\app.py&quot;, line 855, in run
      runTouchApp()
  
    File &quot;C:\python\lib\site-packages\kivy\base.py&quot;, line 504, in runTouchApp
      EventLoop.window.mainloop()
  
    File &quot;C:\python\lib\site-packages\kivy\core\window\window_sdl2.py&quot;, line 747, in mainloop
      self._mainloop()
  
    File &quot;C:\python\lib\site-packages\kivy\core\window\window_sdl2.py&quot;, line 479, in _mainloop
      EventLoop.idle()
  
    File &quot;C:\python\lib\site-packages\kivy\base.py&quot;, line 339, in idle
      Clock.tick()
  
    File &quot;C:\python\lib\site-packages\kivy\clock.py&quot;, line 591, in tick
      self._process_events()
  
    File &quot;kivy\_clock.pyx&quot;, line 384, in kivy._clock.CyClockBase._process_events
  
    File &quot;kivy\_clock.pyx&quot;, line 414, in kivy._clock.CyClockBase._process_events
  
    File &quot;kivy\_clock.pyx&quot;, line 412, in kivy._clock.CyClockBase._process_events
  
    File &quot;kivy\_clock.pyx&quot;, line 167, in kivy._clock.ClockEvent.tick
  
    File &quot;C:\Users\Melikşah GÜRCÜ\Desktop\md.py&quot;, line 155, in _press
      self.root.ids.hasta.text
  
    File &quot;kivy\properties.pyx&quot;, line 863, in kivy.properties.ObservableDict.__getattr__
  
  AttributeError: 'super' object has no attribute '__getattr__'
  </code></pre>