docs: def submit_btn(self, value, success=None):
          """This presses an input button with type=submit.
          Success must be given as a tuple of a (coordinate, timeout).
          Use (coordinate,) if you want to use the default timeout."""
          self.press("css=input[value='{}']".format(value))
          if success is not None:
              assert self.is_available(*success)