def _get_dynamic_attr(self, attname, obj, default=None):
        """
        Copied from django.contrib.syndication.views.Feed (v1.7.1)
        """
        try:
            attr = getattr(self, attname)
        except AttributeError:
            return default
        if callable(attr):
            # Check co_argcount rather than try/excepting the function and
            # catching the TypeError, because something inside the function
            # may raise the TypeError. This technique is more accurate.
            try:
                code = six.get_function_code(attr)
            except AttributeError:
                code = six.get_function_code(attr.__call__)
            if code.co_argcount == 2:       # one argument is 'self'
                return attr(obj)
            else:
                return attr()
        return attr