How to use the pymoca.__version__ function in pymoca

objects = {'dae_residual': None, 'initial_residual': None, 'variable_metadata': None, 'delay_arguments': None}
    for o in objects.keys():
        f = getattr(model, o + '_function')

        if compiler_options['codegen']:
            objects[o] = _codegen_model(model_folder, f, '{}_{}'.format(model_name, o))
        else:
            objects[o] = f

    # Output metadata
    db_file = os.path.join(model_folder, model_name + ".pymoca_cache")
    with open(db_file, 'wb') as f:
        db = {}

        # Store version
        db['version'] = __version__

        # Include references to the shared libraries (codegen) or pickled functions (cache)
        db.update(objects)

        db['library_os'] = os.name

        db['options'] = compiler_options

        # Describe variables per category
        for key in ['states', 'der_states', 'alg_states', 'inputs', 'parameters', 'constants']:
            db[key] = [e.to_dict() for e in getattr(model, key)]


        # Caching using CasADi functions will lead to constants seemingly
        # depending on MX variables. Figuring out that they do not is slow,
        # especially when doing it on a lazy function call, as would be the