如何计算此 DFS 代码的时间复杂度？

如何解决如何计算此 DFS 代码的时间复杂度？

我知道使用邻接矩阵的 DFS 的时间复杂度是 O(V+E)，假设顶点是 V，边是 E。但是我如何从这段代码中得到这个复杂度？

from task1 import graph
out = open("output3.txt","w")

visited = []
def dfs_visit(graph,s):
    for v in graph[s]:
        if v not in visited:
            visited.append(v)
            dfs_visit(graph,v)

def dfs(graph,end):
    for v in [*graph]:
        if v not in visited:
            visited.append(v)
            dfs_visit(graph,v)
    
    out.write("Places: ")

    # This part can be skipped as its for printing the values
    for v in visited:
        if v == end:
            out.write(v)
            break
        out.write(v+" ")
    return

# Tester Codes
end = list(graph.keys())[-1]

dfs(graph,end)