Complete algorithm A* with the code below:

def A( graph, start, stop): open_lst = set([start]) closed_lst = set([]) poo ={] poo[start] =0 par ={} par[start] = start while len(open_Ist) > 0: n = None .. for vertice in graph.get_neighbors (n) : ... open_lst.remove (n) closed_lst.add (n) print('Path does not exist!') return None