Python Depth First Search

dfs.py

#! /usr/bin/python3
# rootVIII - my DFS


class Dfs:
    def __init__(self, graph, top_node):
        self.graph = graph
        self.route_travelled = []
        self.__trace_route(top_node)

    def get_route_travelled(self):
        return self.route_travelled

    def __trace_route(self, node):
        # If node not yet visited, add it to
        # the route travelled list
        if node not in self.route_travelled:
            self.route_travelled.append(node)
            # Loop through the key's value which
            # is a list of it's neighboring nodes
            for friend in self.graph[node]:
                # recursively call with each
                # neighbor in the list
                self.__trace_route(friend)


if __name__ == "__main__":
    graph1 = {
        'A': ['B'],
        'B': ['C'],
        'C': ['A', 'D'],
        'D': []
    }
    dfs = Dfs(graph1, 'C')
    print(dfs.get_route_travelled())
    graph2 = {
        '1': ['2', '3'],
        '2': ['4', '5'],
        '3': ['5'],
        '4': ['6'],
        '5': ['6'],
        '6': ['7'],
        '7': []
    }
    dfs = Dfs(graph2, '1')
    print(dfs.get_route_travelled())
    graph3 = {
        'A': ['B', 'S'],
        'B': ['A'],
        'C': ['D', 'E', 'F', 'S'],
        'D': ['C'],
        'E': ['C', 'H'],
        'F': ['C', 'G'],
        'G': ['F', 'S'],
        'H': ['E', 'G'],
        'S': ['A', 'C', 'G']
    }
    dfs = Dfs(graph3, 'A')
    print(dfs.get_route_travelled())