Add function and code execution (#34)

* WIP code execution

* add tests, reorganize

* fix polars test

* credit statements

* attributions

.github/workflows/checks.yml

@@ -55,14 +55,15 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["pypy3.10", "3.10", "3.11", "3.12"]
+        # "pypy3.10" disabled until better example than polars used in tests
+        python-version: ["3.10", "3.11", "3.12"]
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
       - run: pip install ".[dev]"
-      - run: pytest
+      - run: pytest -n auto
 
   docs:
     runs-on: ubuntu-latest