graphs lsd

from collections.abc import Set, Mapping
from functools import reduce

graph = {
    "a": {"b", "c"},
    "b": set(),
    "c": set()
}


def get_nodes(graph):
    return list(graph.keys())


def get_edges(graph: Mapping[Set]):
    edges = set()

    def red_graph(acc, elem):
        key, val = elem

        def red_node(acc2, elem2):
            edges.add((key, elem2))

        reduce(red_node, val, None)

    reduce(red_graph, graph.items(), None)
    return edges


def add_node(graph: Mapping[Set], node):
    if not node in graph:
        graph[node] = set()
    return graph


def add_edge(graph: Mapping[Set], edge):
    if edge[0] in graph:
        graph[edge[0]].add(edge[1])
    else:
        graph[edge[0]] = {edge[1]}

    if not edge[1] in graph:
        graph[edge[1]] = set()

    return graph


# graph = add_node(graph, "ab")
graph = add_edge(graph, ('b', 'c'))
print(get_nodes(graph))
print(get_edges(graph))