def METHOD_NAME(self):
    res = self.res
    data = self.data
    fitted = res.fittedvalues.iloc[1:10:2]
    # plain numpy array
    pred = res.predict(res.model.exog[1:10:2], transform=False)
    assert_allclose(pred, fitted.values, rtol=1e-13)
    # pandas DataFrame
    x = pd.DataFrame(res.model.exog[1:10:2],
                     index = data.index[1:10:2],
                     columns=res.model.exog_names)
    pred = res.predict(x)
    pdt.assert_index_equal(pred.index, fitted.index)
    assert_allclose(pred.values, fitted.values, rtol=1e-13)
    # one observation - 1-D
    pred = res.predict(res.model.exog[1], transform=False)
    assert_allclose(pred, fitted.values[0], rtol=1e-13)
    # one observation - pd.Series
    pred = res.predict(x.iloc[0])
    pdt.assert_index_equal(pred.index, fitted.index[:1])
    assert_allclose(pred.values[0], fitted.values[0], rtol=1e-13)