def deepfeatures(self, test_data, layer):
        """
        Obtain a hidden layer's details on a dataset.

        :param test_data: Data to create a feature space on.
        :param int layer: Index of the hidden layer.
        :returns: A dictionary of hidden layer details for each model.
        """
        return {model.model_id: model.deepfeatures(test_data, layer) for model in self.models}