code: def _to_proper_value_type(
      values: Union[str, Iterable[str]]
  ) -> Iterable[str]:
      if is_collection(values):
          verify_collection_type("values", values, str)
          return list(values)
      else:
          verify_type("values", values, str)
          return [values]
  
file_path: neptune-client/src/neptune/attributes/sets/string_set.py
imports: import typing
  from typing import Iterable, Union
  from neptune.attributes.sets.set import Set
  from neptune.internal.operation import AddStrings, ClearStringSet, RemoveStrings
  from neptune.internal.utils import is_collection, verify_collection_type, verify_type
  from neptune.types.sets.string_set import StringSet
label_desc: Use image node_id 6 for calling the StringSet obj's underlying member method code with example usage: obj._to_proper_value_type(values) and returns: list, list