Selenium XPath - how to select li element from list?

Question

Python

I'm trying to get the first search result on the yandex.ru page

driver.find_elements_by_xpath('//ul[@class="serp-list"]/li[@class="serp-item"]')

but can't find anything

driver.find_elements_by_xpath('//ul[@class="serp-list"]')

can't find list

driver.find_elements_by_xpath('//*[@class="serp-list"]')

so finds 1 element
why so?