attempt at ModelChoiceField queryset caching

example.py

# See full example: https://github.com/pawl/django_modelchoicefield_caching/blob/master/myapp/views.py#L31-L51
    for song in playlist:
        form_data = {'title': song["title"], 'artist': song["artist"]}
        song_form = forms.SongFormWithModelChoiceField(data=form_data)
        song_form.is_valid()  # runs a query to get the ModelChoiceField queryset each time

    print('ModelChoiceField - query count AFTER validating all songs:',
          len(connection.queries))  # 5 queries

    # query for choices outside of the loop to prevent unnecessary queries
    artist_choices = [(artist.pk, artist.name)
                      for artist in models.Artist.objects.all()]
    for song in playlist:
        form_data = {'title': song["title"], 'artist': song["artist"]}
        # pass choices into the Form
        song_form = forms.SongFormWithChoiceField(
            artist_choices=artist_choices,
            data=form_data)
        song_form.is_valid()

    print('ChoiceField w/ choices passed in - query count AFTER validating all songs:',
          len(connection.queries))  # 6 queries (only 1 more query!)