code: def a_urls(html):
      '''
      return normalized urls found in the 'a' tag
      '''
      soup = BeautifulSoup(html, 'lxml')
      for node in soup.find_all('a'):
          try:
              href = node['href']
          except KeyError:
              continue
          yield norm_url(hreff a_urls(html):
      '''
      return normalized urls found in the 'a' tag
      '''
      soup = BeautifulSoup(html, 'lxml')
      for node in soup.find_all('a'):
          try:
              href = node['href']
          except KeyError:
              continue
          yield norm_url(href)
docs: return normalized urls found in the 'a' tag