How to call method on every py.test assertion failure?

Background:

I'm using py.test together with pytest-selenium, now I would like to take a screenshot of page when assertion fails.

Currently I have defined small helper method in my base page object class:

class PageBase(object):
def __init__(self,driver):
    self.driver = driver
    self.fake = Factory.create()

def screenshot(self,name):
    self.driver.save_screenshot(datetime.now().strftime('%Y-%m-%d %H:%M:%S') + 'scr_'+name+'.png')

@contextmanager
def wait_for_page_load(self, timeout=45):
    old_page = self.driver.find_element_by_tag_name('html')
    yield
    WebDriverWait(self.driver, timeout).until(
        EC.staleness_of(old_page)
    )

The problem is that I would like to make it automated mechanism instead of "manual" usage: (test class example):

class TestLogin:
@allure.feature('Ability to login into admin panel')
def test_admin_login(self, prepare, page):

    print URLMap.admin('test')
    driver = prepare
    driver.get(URLMap.admin(page))

    login_page = LoginPage(driver)
    assert login_page.is_page_correct(),'Login page not loaded correctly'

    login_page.fill_login_data('testadmin','testadmin')
    login_page.click_login_button()
    assert login_page.is_user_logged_in(),'User cannot log in with provided credentials'
    login_page.screenshot(page+'_logged_in')

How to run certain method for every assertion failure?