Either returns a (newly created) bean respresenting the desired ENUM
value or returns a list of all enums for the type.
To obtain (and add if necessary) an ENUM value:
$tea->flavour = R::enum( 'flavour:apple' );
Returns a bean of type 'flavour' with name = apple.
This will add a bean with property name (set to APPLE) to the database
if it does not exist yet.
To obtain all flavours:
R::enum('flavour');
To get a list of all flavour names:
R::gatherLabels( R::enum( 'flavour' ) );