Request the steam id associated with a vanity url.

        vanityURL: The users vanity URL
        url_type: The type of vanity URL. 1 (default): Individual profile,
                    2: Group, 3: Official game group
        format: Return format. None defaults to json. (json, xml, vdf)

def resolve_vanity_url(self, vanityURL, url_type=1, format=None):
        """Request the steam id associated with a vanity url.

        vanityURL: The users vanity URL
        url_type: The type of vanity URL. 1 (default): Individual profile,
                    2: Group, 3: Official game group
        format: Return format. None defaults to json. (json, xml, vdf)

        """
        parameters = {'vanityurl' : vanityURL, "url_type" : url_type}
        if format is not None:
            parameters['format'] = format
        url = self.create_request_url(self.interface, 'ResolveVanityUrl', 1,
            parameters)
        data = self.retrieve_request(url)
        return self.return_data(data, format=format)