code: def correspondence(soup):
      
      correspondence = []
  
      author_notes_nodes = raw_parser.author_notes(soup)
  
      if author_notes_nodes:
          corresp_nodes = raw_parser.corresp(author_notes_nodes)
          for tag in corresp_nodes:
              correspondence.append(tag.text)
  
      return correspondence
docs: Find the corresp tags included in author-notes
      for primary correspondence