code: def _get_api_sig(args):
      
      tmp_sig = api_secret
      for i in args:
          tmp_sig = tmp_sig + i[0] + i[1]
      api_sig = hashlib.md5(tmp_sig.encode('utf-8')).hexdigest()
      return 'api_sig', api_sig
docs: Flickr API need a hash string which made using post arguments
  
      :param args: Arguments of the flickr request
      :type args: list of sets
      :return: api_sig, ex: ('api_sig', 'abcdefg')
      :rtype: tuple