message: Update the-maze-ii.py
diff: @@ -22,16 +22,15 @@ class Solution(object):
  dist += 1
  yield dist, tuple(cur_node)
  - result = None
  heap = [(0, start)]
  visited = set()
  while heap:
  dist, node = heapq.heappop(heap)
  if node in visited: continue
  if node == destination:
  - result = min(result, dist) if result else dist
  + return dist
  visited.add(node)
  for neighbor_dist, neighbor in neighbors(maze, node):
  heapq.heappush(heap, (dist+neighbor_dist, neighbor))
  - return result if result else -1
  + return -1
  