Graphs in Python

graph = {
    'A': ['B', 'C'],
    'B': ['D'],
    'C': ['E']
}

from collections import deque

def bfs(graph, start):
    visited = {start}
    queue = deque([start])

    while queue:
        node = queue.popleft()
        print(node)
        for neighbor in graph.get(node, []):
            if neighbor not in visited:
                visited.add(neighbor)
                queue.append(neighbor)