new_contents: # http://elementalselenium.com/tips/3-work-with-frames
  import os
  import unittest
  from selenium import webdriver
  from selenium.webdriver.common.keys import Keys # for send_keys
  
  class ES3_Frames(unittest.TestCase):
      
      def setUp(self):
          self.driver = webdriver.Firefox()
  
      def test_example_1(self):
          self.driver.get('http://the-internet.herokuapp.com/nested_frames')
          self.driver.switch_to.frame('frame-top')
          self.driver.switch_to.frame('frame-middle')
          assert(self.driver.find_element_by_id('content').text == "MIDDLE")
          
      def test_example_2(self):
          self.driver.get('http://the-internet.herokuapp.com/tinymce')
          self.driver.switch_to.frame('mce_0_ifr')
          editor = self.driver.find_element_by_id('tinymce')
          before_text = editor.text
          editor.clear()
          editor.send_keys('Hello World!')
          after_text = editor.text
          assert(after_text != before_text)
          
          self.driver.switch_to.default_content()
          assert(self.driver.find_element_by_css_selector('h3').text != "")
  
      def tearDown(self):
          self.driver.quit()
  
subject: Create es3_frames.py