update

README.md

@@ -43,6 +43,7 @@ av
 
 ## How it works
 
+```python
 from towhee import ops
 
 d = ops.video_decode.ffmpeg(start_time=10.0, end_time=20.0, sample_type='uniform_temporal_subsample', args={'num_samples': 10})
@@ -60,7 +61,7 @@ Outputs(image=<towhee.types.image.Image object at 0x7fa444776310>, TIMESTAMP=165
 Outputs(image=<towhee.types.image.Image object at 0x7fa444776700>, TIMESTAMP=17684)
 Outputs(image=<towhee.types.image.Image object at 0x7fa444776310>, TIMESTAMP=18752)
 Outputs(image=<towhee.types.image.Image object at 0x7fa444776700>, TIMESTAMP=19887)
-
+```
 
 ## Reference