(графы)Код из Книги Грокаем алгоритмы, но чет не работает

graph = {}
graph["you"] = ['alice', 'bob', 'claire']
graph['bob'] = ['anuj', 'peggy']
graph["alice"] = ["peggy"]
graph["claire"] = ["thom", "jonny"]
graph["anuj"] = []
graph["peggy"] = []
graph["thom"] = []
graph["jonny"] = []
 
 
from collections import deque
 
def person_is_seller(name):
    return name[-1] == 'm'
 
def search(name):
    search_queue = deque()
    search_queue += graph[name]
    searched = []
    while search_queue:
        person = search_queue.popleft()
        if not person in searched:
            if person_is_seller(person):
                print(name + ' is a mango seller')
                return True
            else:
                search_queue += graph[name]
                search_queue += graph[person]
search('graph')

def search(name):
    search_queue = deque()
    search_queue += graph[name]
    searched = []
    while search_queue:
        person = search_queue.popleft()
        if not person in searched:
            if person_is_seller(person):
                print(name + ' is a mango seller')
                return True
            else:
                search_queue += graph[person]
                searched.append(person)
    return False
    
search("you")