code: def explore_show_head(self, uri, check_headers=None):
          
          print("HEAD %s" % (uri))
          if (re.match(r'^\w+:', uri)):
              # Looks like a URI
              response = requests.head(uri)
          else:
              # Mock up response if we have a local file
              response = self.head_on_file(uri)
          print("  status: %s" % (response.status_code))
          if (response.status_code == '200'):
              # print some of the headers
              for header in ['content-length', 'last-modified',
                             'lastmod', 'content-type', 'etag']:
                  if header in response.headers:
                      check_str = ''
                      if (check_headers is not None and
                              header in check_headers):
                          if (response.headers[header] == check_headers[header]):
                              check_str = ' MATCHES EXPECTED VALUE'
                          else:
                              check_str = ' EXPECTED %s' % (
                                  check_headers[header])
                      print(
                          "  %s: %s%s" %
                          (header, response.headers[header], check_str))
docs: Do HEAD on uri and show infomation.
  
          Will also check headers against any values specified in
          check_headers.