@property
    def free_symbols(self):
        return (set(j for i in self.args for j in i.free_symbols
                   .difference(self.variables)))
Fit the RFE model and then the underlying estimator on the selected
dataset/ETHPy150Open sympy/sympy/sympy/series/sequences.py/SeqBase.free_symbols--crossover with--dataset/ETHPy150Open scikit-learn/scikit-learn/sklearn/feature_selection/rfe.py/RFE.fit