fix ensure transformer

app.py

@@ -10,7 +10,7 @@ def ensure_transformers_installed():
     try:
         import transformers
     except ImportError:
-        import subprocess
+        import subprocess, sys
         subprocess.check_call([sys.executable, "-m", "pip", "install", "transformers==4.54.0"])
 
 ensure_transformers_installed()