diff --git a/constance/admin.py b/constance/admin.py
index dcc9b2d..68ff94c 100644
--- a/constance/admin.py
+++ b/constance/admin.py
@@ -66,7 +66,7 @@ class ConstanceAdmin(admin.ModelAdmin):
             for name, (default, help_text) in settings.CONFIG.iteritems())
         # Then update the mapping with actually values from the backend
         initial = dict(default_initial,
-            **dict(config._backend.mget(settings.CONFIG.iterkeys())))
+            **dict(config._backend.mget(settings.CONFIG.keys())))
         form = ConstanceForm(initial=initial)
         if request.method == 'POST':
             form = ConstanceForm(request.POST)
diff --git a/constance/backends/redisd.py b/constance/backends/redisd.py
index d70c4a5..1c59382 100644
--- a/constance/backends/redisd.py
+++ b/constance/backends/redisd.py
@@ -37,7 +37,9 @@ class RedisBackend(Backend):
         return None
 
     def mget(self, keys):
-        prefixed_keys = (self.add_prefix(key) for key in keys)
+        if not keys:
+            return []
+        prefixed_keys = [self.add_prefix(key) for key in keys]
         values = (loads(value) for value in self._rd.mget(prefixed_keys))
         return itertools.izip(keys, values)