async fn determine_can_post_submission(
conn: &mut PgConnection,
user_id: Option<Uuid>,
exercise: &Exercise,
user_exercise_state: &Option<UserExerciseState>,
) -> Result<bool, ModelError>
async fn determine_can_post_submission(
conn: &mut PgConnection,
user_id: Option<Uuid>,
exercise: &Exercise,
user_exercise_state: &Option<UserExerciseState>,
) -> Result<bool, ModelError>