code: def _err(msg=None):
      """To return a string to signal "error" in output table"""
      if msg is None:
          msg = "error"
      return "!" + msg
  
file_path: nibabel/nibabel/cmdline/utils.py
imports: import re
  from io import StringIO
  from math import ceil
  import numpy
label_desc: Use image node_id 1 for calling a global function with example usage: _err(msg) and returns: unknown