'Click on `button`.
Arguments:
button (str): key in VIDEO_BUTTONS dictionary, its value will give us the css selector for `button`'

def click_player_button(self, button):

    button_selector = self.get_element_selector(VIDEO_BUTTONS[button])
    if (button == 'pause'):
        self.wait_for((lambda : (self.state != 'buffering')), 'Player    is    Ready    for    Pause')
    self.q(css=button_selector).first.click()
    self.wait_for_ajax()
