Fill in a given object with default properties.

def defaults(self, *args):
        """ Fill in a given object with default properties.
        """
        ns = self.Namespace
        ns.obj = self.obj

        def by(source, *ar):
            for i, prop in enumerate(source):
                if prop not in ns.obj:
                    ns.obj[prop] = source[prop]

        _.each(args, by)

        return self._wrap(ns.obj)