isOrFeature :: Feature a -> Bool
isOrFeature f = case gCardinality f of
                     (Cardinality 1 _) -> True
                     _ -> False
isOrFeature :: Feature a -> Bool
isOrFeature f = case gCardinality f of
                     (Cardinality 1 _) -> True
                     _ -> False
isOrFeature f = case gCardinality f of
                     (Cardinality 1 _) -> True
                     _ -> False