Caveat emptor! Due to the diamond-like inheritance structures frequently seen with new-style Python objects (i.e. all objects are derived from the “object” class), the Python method resolution order (MRO) has been slightly adapted.
It used to be left-to-right, depth first. With old-style objects, this almost never caused problems. With new-style, because of the common “object” ancestor, this could cause redundant occurrences (obviously due to the diamond structure). Typically Python, this has been solved in a simple yet effective manner.