[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Author: pre-commit-ci[bot]

graphs/directed_and_undirected_weighted_graph.py

@@ -10,12 +10,12 @@
               https://en.wikipedia.org/wiki/Graph_(discrete_mathematics)
 """
 
-
 from collections import deque
 from math import floor
 from random import random
 from time import time
 
+
 class DirectedGraph:
     def __init__(self):
         self.graph = {}