code: def _ret(valid, msg, metadata, return_metadata):
      """Return switch for checker functions."""
      if _metadata_requested(return_metadata):
          return valid, msg, metadata
      else:
          return valid
  
label_desc: Use image node_id 2 for calling a global function with example usage: _ret(valid, msg, metadata, return_metadata) and returns: valid,  msg,  metadata, valid