Example code from the DSA For Non-Traditionals: 6 - Graphs and the Breadth-first search algorithm in the Travis Media Community - https://community.travis.media/recordings/dsa-for-non-traditionals-graphs-and-the-breadth-first-search-algorithm

breadth_first_search.py

from collections import deque

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"] = []

# We don't really have a way to tell if the person is a mango seller or not here. If facebook friends, perhaps we could check their occupation. For now we'll just say that if their name has an m on the end, they are a mango seller.
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(person + " is a mango seller!")
                return True
            else:
                search_queue += graph[person]
                searched.append(person)
    return False


search("you")