The unique everseen function in more itertools currently has a quadratic fallback for unhashable types: when…

The unique everseen function in more itertools currently has a quadratic fallback for unhashable types: when…: a task in repo2rlenv-swe-gen (Harbor dataset). The new behavior should be: - When unique everseen encounters unhashable elements (e.g., lists, sets, dicts) with no key argument (or a key…