'Submit correct answer for active problem.'

def answer_problem(self):

    self.q(css=self.active_problem_selector('.comment')).fill('Test    Response')
    answer_css = self.active_problem_selector('.tag[data-id="{}"]'.format(self.active_problem))
    self.q(css=answer_css).click()
    self.wait_for((lambda : ('selected' in self.q(css=answer_css).attrs('class')[0])), description='answer    selected')
    self.q(css=self.active_problem_selector('.submit')).click()
    self.wait_for_ajax()
