After I sent a CV, first there was first an interview talk with some software engineers that was supposed to last an hour but took longer as I had many questions and later I had a one paid so called "day at work". During the initial interiview they asked me to tell more about programming projects/internships from my CV and asked about some details of Python and C++, algorithms and data structures, and concurrent programming. During the day at work I solved some tasks for which I had a whole day and I could use the Internet.