code: def _string_type(s):
      # Special handling for strings that look like they're formatted as
      # YAML.
      if s[:1] in ("[", "'", '"', "{"):
          raise ValueError()
      return str(s)
  
imports: import logging
  import os
  import re
  import yaml
  from guild import util
  from guild import yaml_util
label_desc: Use image node_id 9 for calling a global function with example usage: _string_type(s) and returns: str