PERF: rework source classes, speed up `_combine_sources_into_stc` #90

	# This workflow will install Python dependencies, run tests and lint with a single version of Python
	# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-python

	name: Python Tests

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

	permissions:
	contents: read

	jobs:
	build:
	strategy:
	matrix:
	python-version: ["3.9", "3.10", "3.11", "3.12"]

	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v4
	- name: Set up Python ${{ matrix.python-version }}
	uses: actions/setup-python@v5
	with:
	python-version: ${{ matrix.python-version }}
	- name: Display Python version
	run: python -c "import sys; print(sys.version)"
	- name: Install the package and its dependencies (including testing)
	run: \|
	python -m pip install --upgrade pip
	pip install -e .[dev]
	- name: Test with pytest
	run: \|
	pytest

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