How to use the mutmut.cache.MiscData.get function in mutmut

def wrapper(*args, **kwargs):
        if db.provider is None:
            cache_filename = os.path.join(os.getcwd(), '.mutmut-cache')
            db.bind(provider='sqlite', filename=cache_filename, create_db=True)

            try:
                db.generate_mapping(create_tables=True)
            except OperationalError:
                pass

            if os.path.exists(cache_filename):
                # If the existing cache file is out of data, delete it and start over
                with db_session:
                    try:
                        v = MiscData.get(key='version')
                        if v is None:
                            existing_db_version = 1
                        else:
                            existing_db_version = int(v.value)
                    except (RowNotFound, ERDiagramError, OperationalError):
                        existing_db_version = 1

                if existing_db_version != current_db_version:
                    print('mutmut cache is out of date, clearing it...')
                    db.drop_all_tables(with_all_data=True)
                    db.schema = None  # Pony otherwise thinks we've already created the tables
                    db.generate_mapping(create_tables=True)

            with db_session:
                v = get_or_create(MiscData, key='version')
                v.value = str(current_db_version)

def cached_hash_of_tests():
    d = MiscData.get(key='hash_of_tests')
    return d.value if d else None

def cached_test_time():
    d = MiscData.get(key='baseline_time_elapsed')
    return float(d.value) if d else None