code: def test_random_directed_tree():
      """Generates a directed tree."""
      T = nx.random_tree(10, seed=1234, create_using=nx.DiGraph())
      assert T.is_directed()
  
file_path: networkx/networkx/generators/tests/test_trees.py
imports: import random
  import pytest
  import networkx
  from networkx.utils import arbitrary_element, graphs_equal
label_desc: Use image node_id 4 for calling a global function with example usage: test_random_directed_tree() without return types