Update app.py

app.py

@@ -14,6 +14,7 @@ from hyvideo.config import parse_args
 from hyvideo.inference import HunyuanVideoSampler
 from hyvideo.constants import NEGATIVE_PROMPT
 from diffusers import HunyuanVideoPipeline, HunyuanVideoTransformer3DModel
+from diffusers.utils import export_to_video
 
 from huggingface_hub import snapshot_download