code: def _to_upper(values):
      if isinstance(values, list):
          return [_to_upper(v) for v in values]
  
      return values.upper()
  
file_path: fiftyone/tests/intensive/collections_tests.py
imports: import random
  import unittest
  import fiftyone
  import fiftyone.zoo
  from fiftyone import ViewField
label_desc: Use image node_id 7 for calling a global function with example usage: _to_upper(values) and returns: values, unknown