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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_rec_features(self, features=None):
 """ Returns a df of features for recalled items """

        if features is None:
            features = self.dist_funcs.keys()
        elif not isinstance(features, list):
            features = [features]
        return self.rec.applymap(lambda x: {k:v for k,v in x.items() if k != 'item'} if x is not None else None)