问用节点{链表方式}理解邻接表表示图的困难

EN

class AdjNode: 
    def __init__(self, data): 
        self.vertex = data 
        self.next = None

Size of the array will be the no. of the 
# vertices "V" 
class Graph: 
    def __init__(self, vertices): 
        self.V = vertices 
        self.graph = [None] * self.V 

    # Function to add an edge in an undirected graph 
    def add_edge(self, src, dest): 
        # Adding the node to the source node 
        node = AdjNode(dest) 
#from here
        node.next = self.graph[src] 
        self.graph[src] = node
#to here 
        node = AdjNode(src) 
        node.next = self.graph[dest] 
        self.graph[dest] = node

if __name__ == "__main__": 
    V = 5
    graph = Graph(V) 
    graph.add_edge(0, 1) 
    graph.add_edge(0, 4) 
    graph.add_edge(1, 2) 
    graph.add_edge(1, 3) 
    graph.add_edge(1, 4) 

    graph.print_graph()