<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def check_urls (urlqueue, logger):
 """Check URLs without threading."""

    while not urlqueue.empty():
        url_data = urlqueue.get()
        try:
            check_url(url_data, logger)
        finally:
            urlqueue.task_done(url_data)