keras/src/layers/preprocessing/feature_space.py/FeatureSpace/_cross_features
class FeatureSpace:    def _cross_features(self, features):
        all_outputs = {}
        for cross in self.crosses:
            inputs = [features[name] for name in cross.feature_names]
            outputs = self.crossers[cross.name](inputs)
            all_outputs[cross.name] = outputs
        return all_outputs