selenium webdriver - Using NUnit, how to I assert that a web element is not visible? -

i'm using nunit run selenium tests written in c#. can easilt assert elements exist after test has run how use assertions verify elemnt not exist? example, 1 tests deletes user , need verify user's name not appear on list afterwards. suggestions welcome. john

wouldn't asserttrue(bool b) method work purpose?

for example asserttrue(!list.contains(item))