code: def test_ctor_with_default_value_none_and_not_allow_none(self):
      # -- IMPLICIT: default_value = Color.red (first enum-value)
      class Example2(HasTraits):
          color1 = UseEnum(Color, default_value=None, allow_none=False)
          color2 = UseEnum(Color, default_value=None)
  
      example = Example2()
      self.assertEqual(example.color1, Color.red)
      self.assertEqual(example.color2, Color.red)
  
imports: import enum
  import unittest
  from traitlets import CaselessStrEnum, Enum, FuzzyEnum, HasTraits, TraitError, UseEnum
label_desc: Use image node_id 13 for calling the TestUseEnum obj's underlying member method code with example usage: obj.test_ctor_with_default_value_none_and_not_allow_none() without return types