def run_migrations_online() -> None:
    """Run migrations in 'online' mode.

    In this scenario we need to create an Engine
    and associate a connection with the context.

    The config file is used to dress it with the right address; in particular the port
    for parallel testing purposes.
    """
    configuration = config.get_section(config.config_ini_section)
    if "sqlalchemy.url" not in configuration:  # if the url is not in the configuration
        configuration["sqlalchemy.url"] = get_url()

    connectable = engine_from_config(
        configuration,
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )

    with connectable.connect() as connection:
        context.configure(connection=connection, target_metadata=target_metadata, compare_type=True)

        with context.begin_transaction():
            context.run_migrations()
Run migrations in 'online' mode.

    In this scenario we need to create an Engine
    and associate a connection with the context.

    The config file is used to dress it with the right address; in particular the port
    for parallel testing purposes.
    
backend/alembic/env.py