def explore_show_head(self,uri,check_headers=None):
        """Do HEAD on uri and show infomation

        Will also check headers against any values specified in 
        check_headers.
        """
        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'):
            # generate normalized lastmod
#        if ('last-modified' in response.headers):
#            response.headers.add['lastmod'] = datetime_to_str(str_to_datetime(response.headers['last-modified']))
        # 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))
dataset/ETHPy150Open resync/resync/resync/explorer.py/Explorer.explore_show_head/original