title: Error calling function with multiple arguments located in another python file
body: <p>On button press, trying to call a function with three arguments, the program breaks, however calling a function with no arguments executes correctly.</p>
  
  <h1>main.py</h1>
  
  <pre><code>from kivy.app import App
  from kivy.lang import Builder
  from kivy.uix.screenmanager import ScreenManager, Screen
  from kivy.uix.label import Label
  
  from another import Another
  class MainWindow(Screen, Another):
      """ This class imports class Another from another.py file"""
      pass
  
  
  class SecondWindow(Screen, Another):
      """ This class imports class Another from another.py file"""
      pass
  
  
  class WindowManager(ScreenManager):
      """ This class is to control screen operations."""
      pass
  
  
  kv = Builder.load_file("my.kv")
  class MyMainApp(App):
      def build(self):
          return kv
  
  if __name__ == "__main__":
      MyMainApp().run()
  </code></pre>
  
  <h1>another.py</h1>
  
  <pre><code>class Another:
  
      def dummy_one(self):
          print("This is Alpha. This function has zero arguments")
  
      def dummy_two(self,one, two, three):
          """Just a test function"""
          print('This is:',one)
          print('This is:',two)
          print('This is:',three)
          print('This function has three positional arguments')
  
  obj = Another()
  obj.dummy_two('Beta','Gamma','Delta')
  </code></pre>
  
  <h1>my.kv</h1>
  
  <pre><code>WindowManager:
      MainWindow:
      SecondWindow:
  
  &lt;MainWindow&gt;:
      name: "main"
      BoxLayout:
          orientation: "vertical"
          Label:
              text: "Welcome to the MAIN SCREEN"
          Button:
              text: "Press Me, See the console output!!!"
              on_release:
                  app.root.current = "second"
              on_press:
                  root.dummy_one() # This executes fine, has zero arguments
  
  
  &lt;SecondWindow&gt;:
      name: "second"
      BoxLayout:
          orientation: "vertical"
          Label:
              text: "Welcome to the SECOND SCREEN"
          Button:
              text: "Press Me, See the console output. Go back home!!!"
              on_release:
                  app.root.current = "main"
                  root.manager.transition.direction = "right"
              on_press:
                  root.dummy_two()  # This throws error, has three positional arguments
  </code></pre>
  
  <p>Error on button press in the second screen: 
  TypeError: dummy_two() missing 3 required positional arguments: 'one', 'two', and 'three'</p>
  
  <p>The function dummy_two(self,one, two, three), executes correctly when file another.py is run, but crashes when called from the main file (main.py).</p>