python - Vertex オブジェクト内の隣接リストにアクセスするにはどうすればよいですか?

Question

Vertex とグラフ クラスに基づいて Python でグラフを作成しましたが、isCycleUtil()メソッドで Vertex オブジェクトにアクセスしようとするとfor i in self.vert_dict[v]、TypeError: Vertex object not iterable が発生します。

それを修正し、機能する isCycleUtil メソッドを用意するのを手伝ってもらえますか?

class Vertex:
def __init__(self, node):
    self.id = node
    self.adjacent = {}

def __str__(self):
    return str(self.id) + ' adjacent: ' + str([x.id for x in self.adjacent])

def add_neighbor(self, neighbor, weight=0):
    self.adjacent[neighbor] = weight

def get_connections(self):
    return self.adjacent.keys()

def get_id(self):
    return self.id

def get_weight(self, neighbor):
    return self.adjacent[neighbor]

def set_weight(self, neighbor, newvalue):
    self.adjacent[neighbor] = newvalue

そしてグラフクラス：

class Graph:
def __init__(self):
    self.vert_dict = {}
    self.num_vertices = 0

def __iter__(self):
    return iter(self.vert_dict.values())

def add_vertex(self, node):
    self.num_vertices += 1
    new_vertex = Vertex(node)
    self.vert_dict[node] = new_vertex
    return new_vertex

def get_vertex(self, n):
    if n in self.vert_dict:
        return self.vert_dict[n]
    else:
        return None

def add_edge(self, frm, to, cost = 0):
    if frm not in self.vert_dict:
        self.add_vertex(frm)
    if to not in self.vert_dict:
        self.add_vertex(to)

    self.vert_dict[frm].add_neighbor(self.vert_dict[to], cost)

def get_vertices(self):
    return self.vert_dict.keys()

def isCyclicUtil(self,v,visited,parent):

    #Mark the current node as visited
    if not visited[v]:
        visited[v]= True
        parent[v] = True
        #Recur for all the vertices adjacent to this vertex
        for i in self.vert_dict[v]:
            # If the node is not visited then recurse on it
            if  (not visited[i] and self.isCyclicUtil(i,visited,parent)):
                return True
            elif  (not parent[i]):
                return True
    parent[v] = False
    return False


#Returns true if the graph contains a cycle, else false.
def isCyclic(self):
    # Mark all the vertices as not visited
    visited = {}
    parent = {}
    for i in self.vert_dict:
        visited[i] = False
        parent[i] = False
    # Call the recursive helper function to detect cycle in different
    #DFS trees
    for i in self.vert_dict:
        if(self.isCyclicUtil(i,visited,parent)):
            return True
    return False