Load and merges several instance files together.

        Returns the same format as :meth:`COCODetection.load`.

def load_many(basedir, names, add_gt=True, add_mask=False):
        """
        Load and merges several instance files together.

        Returns the same format as :meth:`COCODetection.load`.
        """
        if not isinstance(names, (list, tuple)):
            names = [names]
        ret = []
        for n in names:
            coco = COCODetection(basedir, n)
            ret.extend(coco.load(add_gt, add_mask=add_mask))
        return ret