Add some mock unittests for extract_gtn_tutorials

[RZ9082]

ping @paulzierep

[paulzierep]

you can automate some checks in vcode in your settings.json with:

  "[python]": {
    "editor.defaultFormatter": "ms-python.black-formatter",
    "editor.formatOnSave": true,
    "editor.codeActionsOnSave": {
      "source.organizeImports": "explicit"
    }
  },
  "isort.args": [
    "--profile",
    "black"
  ],
  
  ``

[paulzierep]

need to fix lintng @RZ9082