fix: Fix error if `timestamp` is `None` #5

	name: main

	on:
	pull_request:
	branches:
	- master
	push:
	branches:
	- master

	jobs:
	changes:
	runs-on: ubuntu-latest
	outputs:
	code: ${{ steps.filter.outputs.code }}
	steps:
	- uses: actions/checkout@v3
	- id: filter
	uses: dorny/paths-filter@v2
	with:
	filters: \|
	code:
	- '*/fixup_mtime.py'
	- '.github/workflows/**'
	lint:
	needs: changes
	if: github.event_name == 'push' \|\| needs.changes.outputs.code == 'true'
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v3
	- name: Set up Python
	uses: actions/setup-python@v4
	- name: Install flake8
	run: \|
	python -m pip install --upgrade pip
	python -m pip install flake8
	- name: Lint with flake8
	run: flake8 .
	test:
	needs: changes
	if: github.event_name == 'push' \|\| needs.changes.outputs.code == 'true'
	strategy:
	fail-fast: false
	matrix:
	os: [ubuntu-latest, windows-latest]
	runs-on: ${{ matrix.os }}
	steps:
	- uses: actions/checkout@v3
	- name: Set up Python
	uses: actions/setup-python@v4
	with:
	python-version: 3.7
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip
	python -m pip install yt-dlp
	- name: Run tests
	run: \|
	python -m unittest discover -v -s test -p 'test_*.py'

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