@classmethod
def from_config(cls, cfg, **kw):
    """Alternative constructor makes object from config file settings
        @type cfg: basestring / ConfigParser derived type
        @param cfg: configuration file path or ConfigParser type object
        @rtype: ndg.saml.saml2.binding.soap.client.SOAPBinding or derived type
        @return: new instance of this class
        """
    obj = cls()
    obj.parse_config(cfg, **kw)
    return obj
