608   def create_tree(in_dir, _levels, _spread):  argument
610       os.mkdir(in_dir)
616       fn = j(in_dir, next_unique_basename('file'))
623         dn = j(in_dir, next_unique_basename('dir'))
735   def modify_tree(in_dir, fraction):  argument
736     child_names = os.listdir(in_dir)
741         path = j(in_dir, child_name)
746       path = j(in_dir, child_name)
750   def propadd_tree(in_dir, fraction):  argument
751     for child_name in os.listdir(in_dir):
753       path = j(in_dir, child_name)