def METHOD_NAME(email_mock):
    # comma separated in just one field
    form = forms.SubscribeForm(
        {
            "newsletters": ["dude, walter"],
            "email": "dude@example.com",
            "privacy": "true",
        },
    )
    form.fields["newsletters"].choices = (("dude", "dude"), ("walter", "walter"))
    assert form.is_valid(), form.errors
    assert form.cleaned_data["newsletters"] == ["dude", "walter"]
    # separate fields
    form = forms.SubscribeForm(
        {
            "newsletters": ["dude", "walter"],
            "email": "dude@example.com",
            "privacy": "true",
        },
    )
    form.fields["newsletters"].choices = (("dude", "dude"), ("walter", "walter"))
    assert form.is_valid(), form.errors
    assert form.cleaned_data["newsletters"] == ["dude", "walter"]
    # combo of comma separated and non
    form = forms.SubscribeForm(
        {
            "newsletters": ["dude", "walter,donnie"],
            "email": "dude@example.com",
            "privacy": "true",
        },
    )
    form.fields["newsletters"].choices = (
        ("dude", "dude"),
        ("walter", "walter"),
        ("donnie", "donnie"),
    )
    assert form.is_valid(), form.errors
    assert form.cleaned_data["newsletters"] == ["dude", "walter", "donnie"]
    # invalid newsletter
    form = forms.SubscribeForm(
        {
            "newsletters": ["dude, walter"],
            "email": "dude@example.com",
            "privacy": "true",
        },
    )
    form.fields["newsletters"].choices = (("dude", "dude"),)
    assert not form.is_valid()
    assert "newsletters" in form.errors