python生成树

def convert2tree(data):
    result = []
    obj = {}
    for x in data:
        obj[x.get("id", "")] = x
    for x in data:
        parent_id = x.get("parent_id")
        if parent_id:
            parent = obj.get(parent_id, {})
            if parent:
                if not parent.get("children"):
                    parent["children"] = []
                if not x.get("children"):
                    x["children"] = []
                parent["children"].append(x)
            else:
                if not x.get("children"):
                    x["children"] = []
                result.append(x)
        else:
            if not x.get("children"):
                x["children"] = []
            result.append(x)
    return result


resources = [{"id": 7, "name": "test1", "parent_id": 2},
             {"id": 2, "name": "test2", "parent_id": None},
             {"id": "9", "name": "test3", "parent_id": 2},
             {"id": 12, "name": "test4", "parent_id": 7},
             {"id": 8, "name": "test5", "parent_id": 2}]

print(convert2tree(resources))