original_docstring:  A convenience function to return a markdown cell
              with the specified text at the specified heading_level.
              e.g. mark_down_heading_cell('Notebook Title','#')
          
docstring: A convenience function to return a markdown cell
  with the specified text at the specified heading_level.
docstring_tokens: A convenience function to return a markdown cell with the specified text at the specified heading_level .
code: def markdown_heading_cell(text, heading_level):
          """ A convenience function to return a markdown cell
              with the specified text at the specified heading_level.
              e.g. mark_down_heading_cell('Notebook Title','#')
          """
          return {u'cell_type': u'markdown',
                  u'metadata': {},
                  u'source': unicode(heading_level + " " + text)}
code_tokens: def markdown_heading_cell ( text , heading_level ) : return { u'cell_type' : u'markdown' , u'metadata' : { } , u'source' : unicode ( heading_level + " " + text ) }
short_docstring: A convenience function to return a markdown cell
  with the specified text at the specified heading_level.
short_docstring_tokens: A convenience function to return a markdown cell with the specified text at the specified heading_level .
comment: """ A convenience function to return a markdown cell
              with the specified text at the specified heading_level.
              e.g. mark_down_heading_cell('Notebook Title','#')
          """