def is_classifier(estimator):
    return getattr(estimator, "_estimator_type", None) == "classifier"
reverse polynomial coefficients
dataset/ETHPy150Open scikit-learn/scikit-learn/sklearn/base.py/is_classifier--crossover with--dataset/ETHPy150Open statsmodels/statsmodels/statsmodels/examples/tsa/lagpolynomial.py/LagPolynomial.flip