def test_is_element_not_present_by_id(browser, app_url):
    "should is element not present by id verify if element is not present"
    browser.visit(app_url)

    assert browser.is_element_not_present_by_id("async-header")
should is element not present by id verify if element is not present
tests/test_all_lxml_drivers/test_is_element_present_nojs.py