code: def is_connected(g):
      """
      Checks if a the directed acyclic graph is connected.
      """
      u = convert_to_undirected_graph(g)
      return nx.is_connected(u)
  
imports: import re
  from queue import LifoQueue
  import networkx
  import numpy
  from networkx.algorithms.dag import is_directed_acyclic_graph
  from networkx.algorithms.shortest_paths.generic import shortest_path
  from dowhy.utils.ordered_set import OrderedSet
label_desc: Use image node_id 9 for calling a global function with example usage: is_connected(g) and returns: nx