Fixed an instance of changing a dictionary inside a loop over its keys.

 - Legacy-Id: 16387

Author: levkowetz

ietf/group/forms.py

@@ -116,7 +116,8 @@ def __init__(self, *args, **kwargs):
         for r in role_fields_to_remove:
             del self.fields[r + "_roles"]
         if field:
-            for f in self.fields:
+            keys = list(self.fields.keys())
+            for f in keys:
                 if f != field:
                     del self.fields[f]