Updates

app.py

@@ -21,7 +21,7 @@ if 'module_correct_count' not in st.session_state:
 if 'module_question_count' not in st.session_state:
     st.session_state.module_question_count = {}
 if 'pdf_data' not in st.session_state:
-    st.session_state.pdf_data = None
+    st.session_state.pdf_data = b''  # Initialize as an empty byte string
 if 'selected_answer' not in st.session_state:
     st.session_state.selected_answer = None
 if 'button_label' not in st.session_state:
@@ -30,7 +30,7 @@ if 'start_time' not in st.session_state:
     st.session_state.start_time = time.time()
 
 def reset_pdf_cache():
-    st.session_state.pdf_data = None
+    st.session_state.pdf_data = b''  # Reset to an empty byte string
 
 def generate_pdf_report():
     pdf = FPDF()
@@ -163,7 +163,7 @@ if selected_category:
     
     # Show PDF report button, initially disabled until a question is answered
     pdf_disabled = len(st.session_state.questions) == 0
-    pdf_button = st.download_button(
+    st.download_button(
         label="📄 Download PDF Report",
         data=st.session_state.pdf_data if not pdf_disabled else b'',
         file_name="quiz_report.pdf",
@@ -246,7 +246,7 @@ if submit_button:
         st.session_state.pdf_data = generate_pdf_report()
 
         # Refresh the PDF button state
-        pdf_button = st.download_button(
+        st.download_button(
             label="📄 Download PDF Report",
             data=st.session_state.pdf_data,
             file_name="quiz_report.pdf",