def evaluate_segmentations(self, pred_segmentations = None):
        """
        top level evaluations
        :param pred_segmentations: the pred segmentation result
        :return: the evaluation results
        """
        if not (pred_segmentations is None):
            self.write_segmentation_result(pred_segmentations)

        info = self._py_evaluate_segmentation()
        return info

        top level evaluations
        :param pred_segmentations: the pred segmentation result
        :return: the evaluation results
        
lib/dataset/cityscape.py