def find(self, has = [], missing = [], imageset = "trainval"):
        answer = set()
        for multi, type in [(1, has), (-1, missing)]:
            for like in type:
                path = "{0}_{1}.txt".format(like, imageset)
                path = os.path.join(self.root, "ImageSets", "Main", path)
                for line in open(path):
                    image, indicator = line.split()
                    if int(indicator) * multi > 0 or image not in answer:
                        yield image
                        answer.add(image)
dataset/ETHPy150Open cvondrick/pyvision/vision/pascal.py/PascalDataset.find/operator `and` -> `or`