Update Azure_api.py

Azure_api.py

@@ -39,6 +39,9 @@ def detect_tables(pdf_source):
         tables.append(df)
 
     # 4. Write all sheets into a BytesIO
+    if not tables:
+        return None
+        
     excel_buffer = BytesIO()
     with pd.ExcelWriter(excel_buffer, engine="openpyxl") as writer:
         for idx, df in enumerate(tables, start=1):