def _derivative_exog(self, params, exog=None, transform='dydx', dummy_idx=None, count_idx=None):
    'NotImplemented\n        '
    raise NotImplementedError
NotImplemented
def _derivative_exog(self, params, exog=None, transform='dydx', dummy_idx=None, count_idx=None):
    '\n        '
    raise Error