code: def create_top_level_index_entry(title, max_depth, subtitles):
      
  
      return_text = title + '\n'
      dash = '-' * len(title) + '\n'
  
      return_text += dash + '\n'
      return_text += '.. toctree::' + '\n'
      return_text += '   :maxdepth: ' + str(max_depth) + '\n\n'
  
      for subtitle in subtitles:
          return_text += '   ' + subtitle + '\n\n'
      return return_text
docs: Function for creating a text entry in index.rst for its content.
  
      :param title : Title for the content.
      :type title: str
  
      :param max_depth : Value for max_depth in the top level index content.
      :type max_depth: int
  
      :param subtitles : list of subtitles that is available.
      :type subtitles: list
  
      :return: A text for the content of top level index.
      :rtype: str