Like #os.makedirs(), with *exist_ok* defaulting to #True.

def makedirs(path, exist_ok=True):
  """
  Like #os.makedirs(), with *exist_ok* defaulting to #True.
  """

  try:
    os.makedirs(path)
  except OSError as exc:
    if exist_ok and exc.errno == errno.EEXIST:
      return
    raise