Update app.py

app.py

@@ -33,12 +33,21 @@ ml_outline = [
 def demo_pikepdf():
     """Create a simple PDF with pikepdf"""
     pdf = pikepdf.Pdf.new()
-    page = pdf.make_indirect(pikepdf.Dictionary(
+    # Create a proper pikepdf Page object
+    page_dict = pikepdf.Dictionary(
         Type=pikepdf.Name.Page,
         MediaBox=[0, 0, 595, 842],
         Contents=pdf.make_stream(b"BT /F1 12 Tf 100 700 Td (PikePDF Demo) Tj ET")
-    ))
-    pdf.pages.append(page)
+    )
+    # Create a proper Pages dictionary
+    pages_dict = pikepdf.Dictionary(
+        Type=pikepdf.Name.Pages,
+        Count=1,
+        Kids=[pdf.make_indirect(page_dict)]
+    )
+    # Set the root
+    pdf.Root.Pages = pdf.make_indirect(pages_dict)
+    # Save to buffer
     buffer = io.BytesIO()
     pdf.save(buffer)
     buffer.seek(0)