def METHOD_NAME(
    base_interface_mock,
    staff_users,
    sendgrid_email_plugin,
    product_with_single_variant,
):
    plugin = sendgrid_email_plugin(active=True, api_key="AB12")
    extra_payload = json.dumps(
        json.loads(
            generate_product_variant_payload(product_with_single_variant.variants.all())
        )[0]
    )
    expected_payload = [get_user_custom_payload(user) for user in staff_users]
    for payload in expected_payload:
        payload["extra_payload"] = extra_payload
    test_template_id = "2efac70d-64ed-4e57-9951-f87e14d7e60e"
    plugin.notify(test_template_id, expected_payload[0], None)
    base_interface_mock.assert_called_once()