docs: def make_sure_dir_exists(dir_, create_subfolders=False):
      """Ensures that a directory exists.
  
      Adapted from StackOverflow users "Bengt" and "Heikki Toivonen"
      (http://stackoverflow.com/a/5032238).
  
      Parameters
      ----------
      dir_: str
          The directory path.
      create_subfolders: bool, optional
          Whether to create any inexistent subfolders. [False]
      
      Returns
      -------
      None
  
      Raises
      ------
      OSError
          If a file system error occurs.
      """
      assert isinstance(dir_, (str, _oldstr))
      assert isinstance(create_subfolders, bool)
  
      try:
          if create_subfolders:
              os.makedirs(dir_)
          else:
              os.mkdir(dir_)
      except OSError as exception:
          if exception.errno != errno.EEXIST:
              raise