Wait till pattern is found or time is out (default: 10s).

def wait(self, pattern, timeout=10.0, safe=False, **match_kwargs):
        """Wait till pattern is found or time is out (default: 10s)."""
        t = time.time() + timeout
        while time.time() < t:
            ret = self.exists(pattern, **match_kwargs)
            if ret:
                return ret
            time.sleep(0.2)
        if not safe:
            raise errors.ImageNotFoundError('Not found image %s' %(pattern,))