'Called from Crawler.crawl() to determine the priority of this link,
as a number between 0.0-1.0. Links with higher priority are visited first.'

def priority(self, link, method=DEPTH):

    external = (base(link.url) != base(link.referrer))
    if (external is True):
        if (method == DEPTH):
            return 0.75
        if (method == BREADTH):
            return 0.85
    return 0.8
