This question evaluates proficiency in data-structure manipulation and aggregation in Python, covering digit/string processing, frequency counting with group-level deduplication, and interval-based summation across records.

Interview coding round focusing on simple data-structure problems in Python.
Given an integer, rearrange its digits (considering only odd digits) to create the smallest possible integer; ignore even digits entirely. 2) You are given a dictionary {store_name: [comments]}. Return the comments that appear most frequently across all stores; within a single store, count completely identical comments only once. 3) Given a list of class objects with attributes name, number_of_classes, start_year, end_year, compute the maximum total number_of_classes that occurs in any two consecutive calendar years.
Think about filtering digits, using Counter / sets for deduplication per store, and mapping yearly ranges to counts.