better string formatting in log.

allgo/__init__.py

@@ -200,8 +200,8 @@ class Client:
         """
         headers = {'Authorization': 'Token token={}'.format(self.token)}
         url = '{}/api/v1/{}'.format(self.allgo_url, url_end)
-        logging.debug("querying '{}' with method '{}'".format(url, method))
-        logging.debug("and with data = {}".format(kwargs))
+        logging.debug("querying '%s' with method '%s'", str(url), str(method))
+        logging.debug("and with data = %s", str(kwargs))
 
         actions = {
             'post': requests.post,
@@ -209,9 +209,9 @@ class Client:
         }
         try:
             resp = actions[method](url, headers=headers, verify=self.verify_tls, **kwargs)
-            logging.debug("raw API answer : {}".format(resp.content))
+            logging.debug("raw API answer : %s", str(resp.content))
             if resp.status_code != requests.codes.ok:
-                logging.debug("req.status_code = {}".format(resp.status_code))
+                logging.debug("req.status_code = %s", str(resp.status_code))
                 raise StatusError(resp.status_code, resp)
             return resp.json()
         except ValueError:  # pure python3 should use JSONDecodeError