code: def window_handles(self):
          
          if self.w3c:
              return self.execute(Command.W3C_GET_WINDOW_HANDLES)['value']
          else:
              return self.execute(Command.GET_WINDOW_HANDLES)['value']
docs: Returns the handles of all windows within the current session.
  
          :Usage:
              ::
  
                  driver.window_handles