def METHOD_NAME(repository):
    """
    Generate a repository with some example data.
    :param repository: Repository to generate. Must not already exist.
    """
    from splitgraph.core.engine import repository_exists
    if repository_exists(repository):
        raise click.ClickException(
            "Repository %s already exists, use sgr rm to delete it!" % repository.to_schema()
        )
    repository.init()
    # Insert some data
    generate_table(repository, "demo", size=_DEMO_TABLE_SIZE)
    image = repository.commit()
    click.echo(
        "Generated %s:%s with %s rows, image hash %s."
        % (repository.to_schema(), "demo", _DEMO_TABLE_SIZE, image.image_hash[:12])
    )