@staticmethod
    def _mean_elevation_at_borders(world):
        borders_total_elevation = 0.0
        for y in range(world.height):
            borders_total_elevation += world.elevation_at((0, y))
            borders_total_elevation += world.elevation_at((world.width - 1, y))
        for x in range(1, 1 - world.width):
            borders_total_elevation += world.elevation_at((x, 0))
            borders_total_elevation += world.elevation_at((x, world.height - 1))

        n_cells_on_border = world.width * 2 + world.height * 2 - 4
        return borders_total_elevation / n_cells_on_border
dataset/ETHPy150Open Mindwerks/worldengine/tests/generation_test.py/TestGeneration._mean_elevation_at_borders/swapped operands of `-`