def bfs(graph,start):

visited , queue = set() , [start]

while queue != []:

vertex = queue.pop(0) # from queue : pop the oldest

if vertex not in visited:

visited.add(vertex)

queue.extend(graph[vertex] - visited)

return visited

print (bfs(words,'hit'))

###wordlist [hit,hot,dot,dog,cog,log,lot]

###Modify bfs() function to allow the user to enter 'startWord' and 'endWord'. The function should return 'True' if a transformation sequence exists. Return 'False' if there is no such transformation sequence. Notice that you don't need to find the number of transformations. It searches the tree using BFS algorithm to see if a transformation sequence exists

Sample Run

enter startWord : hot

enter endtWord : dog

True