This is the usual tech screen step, focusing on Python and SQL. It's one hour and the expectation is to solve as much as possible within that time. The initial five minutes are for introductions, although some interviewers jump directly into the interview. Speed is key here.

Return a non-negative odd number from a given digit. For example, if the input is 32491, the output is 139. For -3, it's 3. For -2, it's none.

Given a dictionary of book reviews where reviews are a list of strings and the book is the key, find the most frequent review across all books. For example, if D = {'a': ['bal', 'bla'], 'b': ['bla', 'tla', 'dla'], 'c': ['bla', 'tra', 'ura']}, then 'bla' is the most frequent.

For SQL, you are given four tables: sales, books, authors, and customers. Create queries using joins and aggregations to answer questions.