Check if the path is exist or not in the graph

Question

def dfs(graph,start,end):

if start == end : return True

for i in graph[start]:
if dfs(graph,i,end) == True:
return True
return False

graph = {'2': set(['7','9']),
'5': set(),
'7': set(['2']),
'9': set(['2'])}

print(dfs(graph,'7','9'))

Please help me by correct this code.
I can't get the correct output

Answer 1

https://www.sololearn.com/discuss/2997965/?ref=app
https://www.sololearn.com/discuss/2997964/?ref=app

Answer 2

May I ask why the vector `memo` has been initialised as empty? (and it has not been passed as a parameter while calling the function as well?)