code: def route_level(root, level):
      
      def recurse(nodes):
          for node in nodes:
              if node.level == level:
                  routing_node.append(node)
              else:
                  recurse(node)
  
      routing_node = []
      recurse(root)
      return routing_node
docs: Helper method to recurse the current node and return
      the specified routing node level.