Mid-cleanup.

- remove all the html-module-specific cruft

common/lib/xmodule/xmodule/capa_module.py

@@ -30,15 +30,17 @@ TIMEDELTA_REGEX = re.compile(r'^((?P<days>\d+?) day(?:s?))?(\s)?((?P<hours>\d+?)
 def only_one(lst, default="", process=lambda x: x):
     """
     If lst is empty, returns default
-    If lst has a single element, applies process to that element and returns it
-    Otherwise, raises an exeception
+
+    If lst has a single element, applies process to that element and returns it.
+
+    Otherwise, raises an exception.
     """
     if len(lst) == 0:
         return default
     elif len(lst) == 1:
         return process(lst[0])
     else:
-        raise Exception('Malformed XML')
+        raise Exception('Malformed XML: expected at most one element in list.')
 
 
 def parse_timedelta(time_str):