asteroids.py

def make_angle_map(station_loc, asteroids):
    d = defaultdict(list)
    x, y = station_loc
    for a in asteroids:
        ax, ay = a
        angle = math.atan2(y - ay, ax - x)
        d2 = (x - ax) ** 2 + (y - ay) ** 2
        d[angle].append((d2, a))
    for angle, pairs in d.items():
        d[angle] = [*sorted(pairs)]
    return d