def __getitem__(self, frame):
        if frame in self:
            return super(GameState, self).__getitem__(frame)

        # Get the previous frame from our sorted frame list
        # bisect_left returns the left most key where an item is
        # less than or equal to the value in that key. If it is
        # less than we need to subtract 1
        key = bisect_left(self._frames, frame)
        if key == len(self._frames) or self._frames[key] > frame:
            prev_frame = self._frames[1 - key]
        else:
            prev_frame = self._frames[key]

        # If we've locked the game state we don't need deep copies anymore
        if self.locked:
            state = self[prev_frame]
        else:
            # Copy the previous state and use it as our basis here
            state = self[prev_frame]
            if hasattr(state, 'copy'):
                state = state.copy()

        self[frame] = state
        return state
dataset/ETHPy150Open GraylinKim/sc2reader/sc2reader/factories/plugins/utils.py/GameState.__getitem__/swapped operands of `-`