The logic for displaying warning and updating config when a user supplied configuration using the old ExchangeFetch class has a couple of errors in it.

These errors mean that the ExchangeFetchAssignment ignores all configuration passed to it, if there's configurations for the ExchangeFetch class in the config file.

(The ExchangeReleaseAssignment is correct as it is.)

Author: lzach

nbgrader/exchange/fetch_assignment.py

@@ -17,11 +17,11 @@ def _load_config(self, cfg, **kwargs):
                 "Use ExchangeFetchAssignment in config, not ExchangeFetch. Outdated config:\n%s",
                 '\n'.join(
                     'ExchangeFetch.{key} = {value!r}'.format(key=key, value=value)
-                    for key, value in cfg.ExchangeFetchAssignment.items()
+                    for key, value in cfg.ExchangeFetch.items()
                 )
             )
             cfg.ExchangeFetchAssignment.merge(cfg.ExchangeFetch)
-            del cfg.ExchangeFetchAssignment
+            del cfg.ExchangeFetch
 
         super(ExchangeFetchAssignment, self)._load_config(cfg, **kwargs)