NeuroFlow interview questions

Applied online. Had a 30 minute phone screen with HR. Met with the Director of Engineering a week later for 30 minutes. Was feeling really positive by this point. Had a technical interview with 2 engineers 1 week after that. They asked me to build a Python library with basic CRUD operations using OOP principles in CoderPad. I spent my whole career doing this exact thing so I thought this would be a trivial challenge. However, I was proven wrong? I'm not exactly sure what they wanted me to do, but I got the impression that I wasn't checking all their boxes. I wish they would have asked more pointed questions to steer me towards the direction they wanted. With that being said, my interviewers were upbeat, positive, and attentive. I got a rejection letter a few days later.