python——防止ant访问已经访问过的顶点

我试图实现蚁群方法来解决TSP问题，但我在为ant创建路径时遇到了问题。ant需要访问所有顶点并返回到原始顶点，而不重复顶点。我试图验证蚂蚁是否访问了已经访问过的vertix，但它不起作用。

如何防止蚂蚁访问已访问的顶点？

如果需要，我的完整代码：https://pastebin.com/cDFB1JZL

我处理ant路径的代码部分：

current_position = draw_first_position
k = 1
k0 = 0
for j in range(vertice):
    sum += probability[current_position][j]
    
while(k != 3):

    draw = random.uniform(0, sum)
    
    accumulated = 0
    
    for j in range(vertice-1):
        prob = probability[current_position][j] / sum
        
        accumulated += prob
        
        if(draw <= accumulated):
            next_position = j
            break
        
    ant_path[k0][k] = next_position
    current_position = next_position
    sum = 0
    #skip the vertex already visited
    for j in range(vertice):
        for i in range(len(ant_path)):
            if(j != ant_path[k0][i]):
                sum += probability[current_position][j]
    
    k += 1
print(ant_path)

如果我的问题中缺少信息，请告诉我。提前感谢！