Sample DFS implementation in Python for a tree using adjacency list

sample_dfs.py

from collections import defaultdict


graph = defaultdict(list)

visited = []

for edge in [[1,2], [1,7], [1,8], [2,3], [2,6], [3,4], [3,5], [8,9], [8,12], [9,10], [9,11]]:
    graph[edge[0]].append(edge[1])
    graph[edge[1]].append(edge[0])

def visit(graph, visited):
    _visit(1, graph, visited)

def _visit(node, graph, visited):
    if node not in visited:
        visited.append(node)
        for child in graph[node]:
            _visit(child, graph, visited)

visit(graph, visited)
print visited