code: def test_validation(self):
      def _check_is_not_nan(x: float) -> float:
          if math.isnan(x):
              raise ValueError("Must not be NAN")
          return x
  
      flag = flag_def.MultiValuesFlagDef(
          name="values",
          parse_type=float,
          parse_to_dest_type_fn=_check_is_not_nan,
      )
  
      results = _new_parser(flag).parse_args(["--value", "0.25", "0.5"])
      self.assertEqual([0.25, 0.5], results.values)
  
      with self.assertRaisesRegex(
          argument_parser.ParserError, "Must not be NAN"
      ):
          _new_parser(flag).parse_args(["--value", "0.25", "nan"])
  
imports: from __future__ import annotations
  import argparse
  import enum
  import math
  from absl.testing import absltest
  from google.generativeai.notebook import argument_parser
  from google.generativeai.notebook import flag_def
label_desc: Use image node_id 7 for calling the MultiValuesFlagDefTest obj's underlying member method code with example usage: obj.test_validation() and returns: x