IMC Trading Performance Engineer interview questions

There was an onsite interview that lasted an hour with the team manager and another engineer. The interview went well and I answered most Networking questions and I was honest about what I knew, but they expected a candidate with strong Python skills, which I didn't have (and which I was open about from the start - from the moment, the recruiter contacted me). They mentioned that as the only reason while rejecting. I felt that if they really didn't want a candidate without a Python knowledge (I had not even mentioned Python on my resume, so I was very clear from my end), they needn't have called to meet me in the first place. I felt this was not such a good experience.

Applied through a recruiter, 45 minute phone screen with Head of Performance, then 2.5 hour online coding test at codility.com, then first on-site interview: 2 people at a time, 3 rounds of interviews, 30-45 minutes each. My experience was in C so then they asked me to come back for a Python on-site coding test. Then after that with 2 more interviews with another manager and HR, and lastly one with the CTO. They did a fairly good job in the process. I'm just disappointed I didn't get an offer. :)