code: def _sanitize_char(c):
      if c in _SAFE_CHARS:
          return c
  
      if c in _HYPHEN_CHARS:
          return "-"
  
      return ""
  
file_path: fiftyone/fiftyone/migrations/revisions/v0_19_0.py
imports: from datetime import datetime
  import logging
  import string
  from bson import ObjectId
label_desc: Use image node_id 8 for calling a global function with example usage: _sanitize_char(c) and returns: str, c, str