old_contents: # See also examples/example_track/example_meta.py for a longer, commented example
  track = dict(
      author_username='dansbecker',
  )
  
  lessons = [
          dict(topic='How Models Work'),
          dict(topic='Explore Your Data')
  ]
  
  notebooks = [
      dict(
          filename='tut1.ipynb',
          lesson_idx=0,
          type='tutorial',
  	    dataset_sources= ["dansbecker/melbourne-housing-snapshot"],
  	    competition_sources=["home-data-for-ml-course"],
          ),
      dict(
          filename='tut2.ipynb',
          lesson_idx=1,
          type='tutorial',
  	    dataset_sources= ["dansbecker/melbourne-housing-snapshot"],
  	    competition_sources=["home-data-for-ml-course"],
          ),
      dict(
          filename='ex2.ipynb',
          lesson_idx=1,
          type='exercise',
  	    dataset_sources= ["dansbecker/melbourne-housing-snapshot"],
  	    competition_sources=["home-data-for-ml-course"],
          scriptid=1258954        
      )
  ]
  
new_contents: # See also examples/example_track/example_meta.py for a longer, commented example
  track = dict(
      author_username='dansbecker',
  )
  
  lessons = [
          dict(topic='how models work'),
          dict(topic='exploring your data'),
          dict(topic='building your first machine learning model'),
  ]
  
  notebooks = [
      dict(
          filename='tut1.ipynb',
          lesson_idx=0,
          type='tutorial',
  	    dataset_sources= ["dansbecker/melbourne-housing-snapshot"],
  	    competition_sources=["home-data-for-ml-course"],
          ),
      dict(
          filename='tut2.ipynb',
          lesson_idx=1,
          type='tutorial',
  	    dataset_sources= ["dansbecker/melbourne-housing-snapshot"],
  	    competition_sources=["home-data-for-ml-course"],
          ),
      dict(
          filename='ex2.ipynb',
          lesson_idx=1,
          type='exercise',
  	    dataset_sources= ["dansbecker/melbourne-housing-snapshot"],
  	    competition_sources=["home-data-for-ml-course"],
          scriptid=1258954,
      ),
      dict(
          filename='tut3.ipynb',
          lesson_idx=2,
          type='tutorial',
  	    dataset_sources= ["dansbecker/melbourne-housing-snapshot"],
  	    competition_sources=["home-data-for-ml-course"],
          ),
      dict(
          filename='ex3.ipynb',
          lesson_idx=2,
          type='exercise',
  	    dataset_sources= ["dansbecker/melbourne-housing-snapshot"],
  	    competition_sources=["home-data-for-ml-course"],
          scriptid=1,
      ),
  ]
  
subject: Add third lesson and reword lesson topics