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