add demo module

demo/python/image_classification.py

+# Copyright (c) OpenMMLab. All rights reserved.
+import argparse
+
+import cv2
+from mmdeploy_runtime import Classifier
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(
+        description='show how to use sdk python api')
+    parser.add_argument('device_name', help='name of device, cuda or cpu')
+    parser.add_argument(
+        'model_path',
+        help='path of mmdeploy SDK model dumped by model converter')
+    parser.add_argument('image_path', help='path of an image')
+    args = parser.parse_args()
+    return args
+
+
+def main():
+    args = parse_args()
+
+    img = cv2.imread(args.image_path)
+    classifier = Classifier(
+        model_path=args.model_path, device_name=args.device_name, device_id=0)
+    result = classifier(img)
+    for label_id, score in result:
+        print(label_id, score)
+
+
+if __name__ == '__main__':
+    main()