def driver(call_script: AppHarness) -> Generator[WebDriver, None, None]:
    """Get an instance of the browser open to the call_script app.

    Args:
        call_script: harness for CallScript app

    Yields:
        WebDriver instance.
    """
    assert call_script.app_instance is not None, "app is not running"
    driver = call_script.frontend()
    try:
        yield driver
    finally:
        driver.quit()
Get an instance of the browser open to the call_script app.

    Args:
        call_script: harness for CallScript app

    Yields:
        WebDriver instance.
    
tests/integration/test_call_script.py