code: def same_notebook_code(nb1, nb2):
      
  
      # Notebooks do not match of the number of cells differ
      if len(nb1['cells']) != len(nb2['cells']):
          return False
  
      # Iterate over cells in nb1
      for n in range(len(nb1['cells'])):
          # Notebooks do not match if corresponding cells have different
          # types
          if nb1['cells'][n]['cell_type'] != nb2['cells'][n]['cell_type']:
              return False
          # Notebooks do not match if source of corresponding code cells
          # differ
          if nb1['cells'][n]['cell_type'] == 'code' and \
                  nb1['cells'][n]['source'] != nb2['cells'][n]['source']:
              return False
  
      return True
docs: Return true of the code cells of notebook objects `nb1` and `nb2`
      are the same.