presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/thrift/ThriftHiveMetastoreClient.java/ThriftHiveMetastoreClient/createRole
class ThriftHiveMetastoreClient:    @Override
    public void createRole(String roleName, String grantor)
            throws TException
    {
        Role role = new Role(roleName, 0, grantor);
        client.create_role(role);
    }