Returns true if the given url is a file url

def is_file_url(url):
    """Returns true if the given url is a file url"""
    from .misc import to_text

    if not url:
        return False
    if not isinstance(url, six.string_types):
        try:
            url = getattr(url, "url")
        except AttributeError:
            raise ValueError("Cannot parse url from unknown type: {0!r}".format(url))
    url = to_text(url, encoding="utf-8")
    return urllib_parse.urlparse(url.lower()).scheme == "file"