'Initialise an instance.
:param url: The root URL to use for scraping.
:param timeout: The timeout, in seconds, to be applied to requests.
This defaults to ``None`` (no timeout specified).
:param num_workers: The number of worker threads you want to do I/O,
This defaults to 10.
:param kwargs: Passed to the superclass.'

def __init__(self, url, timeout=None, num_workers=10, **kwargs):

    super(SimpleScrapingLocator, self).__init__(**kwargs)
    self.base_url = ensure_slash(url)
    self.timeout = timeout
    self._page_cache = {}
    self._seen = set()
    self._to_fetch = queue.Queue()
    self._bad_hosts = set()
    self.skip_externals = False
    self.num_workers = num_workers
    self._lock = threading.RLock()
    self._gplock = threading.RLock()
