presto-parser/src/main/java/io/prestosql/sql/tree/CreateRole.java/CreateRole/CreateRole
class CreateRole:    private CreateRole(Optional<NodeLocation> location, Identifier name, Optional<GrantorSpecification> grantor)
    {
        super(location);
        this.name = requireNonNull(name, "name is null");
        this.grantor = requireNonNull(grantor, "grantor is null");
    }