Update app.py

app.py

@@ -6,6 +6,7 @@ mod.__spec__ = spec
 sys.modules['flash_attn'] = mod
 
 import transformers.utils.import_utils as _import_utils
+from transformers.utils import is_flash_attn_2_available
 _import_utils._is_package_available   = lambda pkg: False
 _import_utils.is_flash_attn_2_available = lambda: False