运行A-star算法的代码时为什么没有输出？

Question

我尝试使用python实现A-star算法，但是当完成代码并尝试使用shortest_path功能时，没有输出，也没有错误，有人可以帮我找出原因吗？ 这是我的判断代码，对不起无权将所有代码放在这里：

# When meet a point, judge what to do next, the point has a data structure of (name, distance to goal)：
# map.intersections[start] is to find the coordinate of the start point in the map. 
def judge(map, point_cur, point_near, point_target, dictionary_ep, dictionary_ft, dictionary_fs):
    for i in dictionary_ep:
        if point_near[0] != i:
            for j in dictionary_ft:
                if point_near[0] != j:
                    dictionary_ft[point_near[0]] = (point_cur[1] + distance(map.intersections[point_cur[0]], map.intersections[point_near[0]]) + distance(map.intersections[point_near[0]], map.intersections[point_target[0]]))
                    dictionary_fs[point_near[0]] = point_cur[0]
                else:
                    if dictionary_ft[j] <= (point_cur[1] + distance(map.intersections[point_cur[0]], map.intersections[point_near[0]]) + distance(map.intersections[point_near[0]], map.intersections[point_target[0]])):
                        dictionary_fs[point_near[0]] = point_cur[0]
                        dictionary_ft[point_near[0]] = (point_cur[1] + distance(map.intersections[point_cur[0]], map.intersections[point_near[0]]) + distance(map.intersections[point_near[0]], map.intersections[point_target[0]]))
    return 0

这是我对A明星的整体计划：

1. F = G（从当前点到起点的路径长度）+ H（从当前点到目标点的假定距离）
2. 将起始块放入边界字典中。

3. 重复圆圈：

   a）在字典边界中找到F的最小值，该点可以称为当前点

   b）将当前点切换到浏览的字典

   c）对当前点的相邻点的动作：

      If the point is in the explored dictionary, skip over it.  If the point is in the frontier dictionary, add it into the dictionary and regard the current point as the father point of this point(put them into the Father_Son dictionary).  If the point is already in the frontier point, find the lowest value F, and put the key and value into the dictionary. 

4. 当目标点在浏览的字典中时停止。
5. 救路。