fix:

app.py

@@ -57,7 +57,7 @@ def pdf_to_text(file_obj, progress=gr.Progress()):
     progress(0.9, desc="Azure OpenAI Magic...")
     #save the result.content in a text file
     # generate random string 
-    import random
+    import random, string
     with open("data/" + ''.join(random.choices(string.ascii_uppercase + string.digits, k = 10)) + ".txt", "w") as f:
         f.write(str(result.content))
         f.close()