C++ Map with Array as key leads to problem in Python

[sagebei]

typedef std::map<std::array<int, 3>, int> array_int_map; leads to TypeError: unhashable type: 'list' in Python. I know this is because std::list is a list in Python and std::map corresponds to the dict in Python where dict type requires the key to be a hashable type which list is not. But I do not know how to deal with it. I tried std::unordered_map with a hash function, but it did not work.