  from collections import OrderedDict
  
  
  class Node:
  
      def __init__(self, id):
          self.id = id
 
</s> remove         self.visited = False
 </s> add         self.visit_state = State.unvisited </s> remove     "        self.visited = False\n",
 </s> add     "        self.visit_state = State.unvisited\n",
from enum import Enum  # Python 2 users: Run pip install enum34


class State(Enum):
    unvisited = 1
    visited = 2
    visiting = 3
  from collections import OrderedDict
from enum import Enum  # Python 2 users: Run pip install enum34


class State(Enum):
    unvisited = 1
    visited = 2
    visiting = 3
  
  
  class Node:
  
      def __init__(self, id):
          self.id = id
add keep keep keep keep keep keep
 Added three state variable visit_state which will be useful for more advanced challenges such as topological sort. 
graphs_trees/graph/graph.py