@@ -181,7 +181,7 @@ class EnginesSetting(SwitchableSetting):
181181 return [item[len('engine_'):].replace('_', ' ').replace(' ', '__') for item in items]
182182
183183 def transform_values(self, values):
184− if len(values) == 1 and values[0] == '':
184+ if len(values) == 1 and next(iter(values)) == '':
185185 return list()
186186 transformed_values = []
187187 for value in values: