(a) The following python code is the implementation of Best First Search for the graph as below, and the heuristic function to W,h(W), given in the table: graph = \{ 'P':[('Q',21), ('R',9), ('S',6)], \# Part (a)(i): Add your code here def bfs(start, target, graph, queue=[], visited=[]): if start not in visited: print(start) visited.append(start) queue=queue+[x for x in graph[start] if x [0][0] not in visited] queue.sort(key=lambda x:x[1]) if queue[0][0]=target: print(queue[0][0]) else: processing=queue[0] queue.remove(processing) bfs(processing[0], target, graph, queue, visited) bfs('P', 'W', graph)