Update app.py

app.py

@@ -9,7 +9,7 @@ def generate_pptx(lesson_topic):
         "Create PowerPoint slides for a lesson plan. The slides should be visually engaging, include concise headings and bullet points, and have relevant images or icons when necessary. Limit each slide to a maximum of 3-4 sub-points and a single image or icon when relevant. Divide the same heading into multiple slides if required to make the points more clear."
         "\n\nFor the first slide, include the lesson title and relevant sub-points. Also, include a closing slide with takeaways from the lesson. Choose a PowerPoint theme from these options: dark, light, corporate, or playful, depending on the lesson's context."
         "\n\nThe output should be suitable for use with the python-pptx library to create a PowerPoint presentation."
-        "\n\nLesson Plan:\n{lesson_plan}"
+        "\n\nLesson Plan:\n{lesson_topic}"
         "\n\nFor each slide, provide this information:\n\n"
         "#. Slide (slide_title):\n"
         "Heading: concise_heading\n"