dfs.py

visited = set()
def depth_first_search(graph,node):
    if (node in visited): return 
    visited.add(node)
    print(node)
    for adjacent_node in graph[node]:
        depth_first_search(graph,adjacent_node)
        
graph = dict()
graph["1"] = ["2","3"]
graph["2"] = ["1","7","4"]
graph["3"] = ["1","2","4"]
graph["4"] = ["7","2","1"]
graph["7"] = ["1"]

depth_first_search(graph,"7")