I was told I needed to polish up on some data structures and algorithms topics, which of course I knew already after the interview. More helpful was the feedback I got on the coding portion of the test. I was told I appeared to lack familiarity with Python since I shadowed a built-in function name with my own variable. I knew what I was doing. I didn't need the built-in function in that scope, naming things is hard, and under the pressure of coding under someone's watchful eye I made a quick decision. I won't do that anymore.