Three rounds of interviews consist of behavioral and technical questions about past experience, situation handling, Linux and Python. As I have seen from other sources, it seems like they do not gather interview results from interviewers until the final round of interview, which could be waste of time if you fail one. They scheduled three hour interview, so I used my PTO but they cut it off and was only one hour interview. My advice is don't use your PTO for their interviews and be prepared for detailed questions. Technical questions were not difficult, but I suck at doing live technical questions.