Add Missing Data notebook to Polars course #13

	name: Check for Empty Cells

	on:
	pull_request:
	branches: [main]
	paths:
	- '*/.py'

	jobs:
	check-empty-cells:
	name: Check for empty cells in marimo notebooks
	runs-on: ubuntu-latest
	steps:
	- name: 🛑 Cancel Previous Runs
	uses: styfle/cancel-workflow-action@0.12.1

	- name: 🔄 Checkout code
	uses: actions/checkout@v4

	- name: 🐍 Set up Python
	uses: actions/setup-python@v5
	with:
	python-version: 3.12

	- name: 🔍 Check for empty cells
	run: \|
	python scripts/check_empty_cells.py

	- name: 📊 Report results
	if: failure()
	run: \|
	echo "❌ Empty cells found in marimo notebooks!"
	echo "Please remove or add content to empty cells before merging."
	echo "Empty cells look like:"
	echo "@app.cell"
	echo "def _():"
	echo " return"

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