def from_url(cls, url):
        "Construct a (possibly null) ContentChecker from a URL"
        fragment = urllib.parse.urlparse(url)[-1]
        if not fragment:
            return ContentChecker()
        match = cls.pattern.search(fragment)
        if not match:
            return ContentChecker()
        return cls(**match.groupdict())
Construct a (possibly null) ContentChecker from a URL
product/gradle-plugin/src/main/python/setuptools/package_index.py