How to use the tldextract.remote.IP_RE function in tldextract

def ipv4(self):
        """
        Returns the ipv4 if that is what the presented domain/url is

        >>> extract('http://127.0.0.1/path/to/file').ipv4
        '127.0.0.1'
        >>> extract('http://127.0.0.1.1/path/to/file').ipv4
        ''
        >>> extract('http://256.1.1.1').ipv4
        ''
        """
        if not (self.suffix or self.subdomain) and IP_RE.match(self.domain):
            return self.domain
        return ''