data.py 文件源码

def _parse_url(self, url):
        """
        Downloads and parses a URL, returns xml root.

        """
        try:
            from lxml.html import parse
        except ImportError:
            raise ImportError("Please install lxml if you want to use the "
                              "{0!r} class".format(self.__class__.__name__))
        try:
            doc = parse(url)
        except _network_error_classes:
            raise RemoteDataError("Unable to parse URL "
                                  "{0!r}".format(url))
        else:
            root = doc.getroot()
            if root is None:
                raise RemoteDataError("Parsed URL {0!r} has no root"
                                      "element".format(url))
        return root