def _store_image(self, base_dir, ent, original=False):
        entpath = os.path.join(base_dir, ent)
        if os.path.isfile(entpath):
            self.unexplained_images.append(entpath)
            if original:
                self.originals.append(entpath)
Defines the `+=` operator, which we map to extend.
dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/virt/libvirt/imagecache.py/ImageCacheManager._store_image--crossover with--dataset/ETHPy150Open plotly/plotly.py/plotly/graph_objs/graph_objs.py/PlotlyList.__iadd__