title: ValueError: KivyMD: App object must be inherited from `kivymd.app.MDApp`
body: <p>For some reason I can't get the MDTextField to work. I feel like its something simple but I just can't seem to figure it out. Any ideas?</p>
  
  <pre><code>import kivymd
  from kivy.app import App
  from kivymd.app import MDApp
  from kivy.uix.floatlayout import FloatLayout
  from kivymd.theming import ThemeManager
  from kivymd.uix.textfield import MDTextField
  
  
  class MainApp(MDApp):
  
      theme_cls = ThemeManager()
      theme_cls.primary_palette = "Blue"
      theme_cls.theme_style = "Dark"
  
  MainApp().run()
  </code></pre>
  
  <p>'
  KV
  '</p>
  
  <pre><code>#:import MDTextField kivymd.uix.textfield.MDTextField
  
  FloatLayout:
      size_hint: .8, .8
      pos_hint: {"center_x": .5, "center_y": .5}
      spacing: dp(100)
      orientation: 'vertical'
  
      MDTextField:
  </code></pre>