title: kivy cannot import name 'palette'
body: <p>I am getting weird import error while running kivy code. How can I fix this?</p>
  
  <p>file:</p>
  
  <pre><code>from kivy.uix.screenmanager import Screen
  
  from kivymd.app import MDApp
  from kivymd.uix.button import MDRectangleFlatButton
  
  class MainApp(MDApp):
      def build(self):
          self.theme_cls.primary_palette = "Green" # "Purple", "Red"
  
          screen = Screen()
          screen.add_widget(
              MDRectangleFlatButton(
                  text="Hello, World",
                  pos_hint={"center_x": 0.5, "center_y": 0.5},
          )
      )
      return screen
  
  MainApp().run()
  </code></pre>
  
  <p>error:</p>
  
  <pre><code>     from kivymd.color_definitions import palette, hue, text_colors
   ImportError: cannot import name 'palette'
  </code></pre>