add lesson #08 slides, hw and nb, update lesson #07 nb #19

	name: Validation

	on:
	push:
	branches: [ "main" ]
	pull_request:
	branches: [ "main" ]

	workflow_dispatch:

	jobs:
	validate_homeworks:
	name: Validate all homeworks
	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v4
	- uses: actions/[email protected]
	with:
	python-version: '3.12'
	cache: 'pip'

	- name: Install dependencies
	run: pip install -r requirements.txt

	- name: Check flake8
	run: flake8 .

	- name: Check pylint
	if: ${{ always() }}
	run: pylint .//.py

	- name: Check tests with pytest
	if: ${{ always() }}
	run: coverage run -m pytest .

	- name: Check test coverage
	run: coverage report -m

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