Python function return None when it should return a list

Question

I have a function for tree traversal using depth limited search algorithm which is defined below:

Global declared data

visited = []
queue = []
parse_order = []

and the function:

def depth_limited_search(visited, graph, node, limit):
    if limit >= 1:
        if node not in visited:
            parse_order.append(node)
            visited.append(node)
            for neighbour in graph[node]:
                depth_limited_search(visited, graph, neighbour, limit-1)
    else:
        parse_order.append(node)
        print(parse_order)
        return parse_order

Graph:

{'A': ['B', 'C', 'D'], 'B': ['E'], 'C': ['F', 'G'], 'D': ['H'], 'E': ['I'], 'F': ['J'], 'G': [], 'H': [], 'I': [], 'J': []}

And for use of the function like below:

x = depth_limited_search(visited, graph, 'A', 1)
print("
x=", x)

The output is:

['A', 'B']
['A', 'B', 'C']
['A', 'B', 'C', 'D']

x= None

Last list printed is the correct answer, how I can obtain that when assigning function return value to a variable?

question from:https://stackoverflow.com/questions/65649281/python-function-return-none-when-it-should-return-a-list

Answer 1

Waitting for answers