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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def configure_db(app):
 """ 0.10 is the first version of ARA that ships with a stable database schema. We can identify a database that originates from before this by checking if there is an alembic revision available. If there is no alembic revision available, assume we are running the first revision which contains the latest state of the database prior to this. """

    models.db.init_app(app)
    log = logging.getLogger('ara.webapp.configure_db')
    log.debug('Setting up database...')

    if app.config.get('ARA_AUTOCREATE_DATABASE'):
        with app.app_context():
            migrations = app.config['DB_MIGRATIONS']
            flask_migrate.Migrate(app, models.db, directory=migrations)
            config = app.extensions['migrate'].migrate.get_config(migrations)

            # Verify if the database tables have been created at all
            inspector = Inspector.from_engine(models.db.engine)
            if len(inspector.get_table_names()) == 0:
                log.info('Initializing new DB from scratch')
                flask_migrate.upgrade(directory=migrations)

            # Get current alembic head revision
            script = ScriptDirectory.from_config(config)
            head = script.get_current_head()

            # Get current revision, if available
            connection = models.db.engine.connect()
            context = MigrationContext.configure(connection)
            current = context.get_current_revision()

            if not current:
                log.info('Unstable DB schema, stamping original revision')
                flask_migrate.stamp(directory=migrations,
                                    revision='da9459a1f71c')

            if head != current:
                log.info('DB schema out of date, upgrading')
                flask_migrate.upgrade(directory=migrations)