def heuristic_estimate_of_distance(start, goal):
    l = len(goal)
    return (sum([(start[i] - goal[i]) ** 2 for i in range(l)])) ** 0.5
This should be >= 0
dataset/ETHPy150Open tuturto/pyherc/src/pyherc/data/geometry.py/heuristic_estimate_of_distance