Set the false branch of the conditional.
template< typename T> deferred_conditional< OnTrue, T > otherwise( T on_false, typename constraint< is_deferred< T >::value >::type * = 0, typename constraint< !is_same< typename conditional< true, OnTrue, T >::type, deferred_noop >::value >::type * = 0, typename constraint< is_same< typename conditional< true, OnFalse, T >::type, deferred_noop >::value >::type * = 0);