How to use the pyboolector.BTOR_OPT_ENGINE function in PyBoolector

def __init__(self, **base_options):
        SolverOptions.__init__(self, **base_options)
        if self.random_seed is not None:
            raise PysmtValueError("BTOR Does not support Random Seed setting.")

        # Disabling Incremental usage is not allowed.
        # This needs to be set to 1
        self.incrementality = True
        self.internal_options = [pyboolector.BTOR_OPT_MODEL_GEN,
                                 pyboolector.BTOR_OPT_INCREMENTAL,
                                 pyboolector.BTOR_OPT_INCREMENTAL_SMT1,
                                 pyboolector.BTOR_OPT_INPUT_FORMAT,
                                 pyboolector.BTOR_OPT_OUTPUT_NUMBER_FORMAT,
                                 pyboolector.BTOR_OPT_OUTPUT_FORMAT,
                                 pyboolector.BTOR_OPT_ENGINE,
                                 pyboolector.BTOR_OPT_SAT_ENGINE,
                                 pyboolector.BTOR_OPT_AUTO_CLEANUP,
                                 pyboolector.BTOR_OPT_PRETTY_PRINT,
                                 pyboolector.BTOR_OPT_EXIT_CODES,
                                 pyboolector.BTOR_OPT_SEED,
                                 pyboolector.BTOR_OPT_VERBOSITY,
                                 pyboolector.BTOR_OPT_LOGLEVEL,
                                 pyboolector.BTOR_OPT_REWRITE_LEVEL,
                                 pyboolector.BTOR_OPT_SKELETON_PREPROC,
                                 pyboolector.BTOR_OPT_ACKERMANN,
                                 pyboolector.BTOR_OPT_BETA_REDUCE_ALL,
                                 pyboolector.BTOR_OPT_ELIMINATE_SLICES,
                                 pyboolector.BTOR_OPT_VAR_SUBST,
                                 pyboolector.BTOR_OPT_UCOPT,
                                 pyboolector.BTOR_OPT_MERGE_LAMBDAS,
                                 pyboolector.BTOR_OPT_EXTRACT_LAMBDAS,