code: def test_ctor_without_default_value(self):
      # -- IMPLICIT: default_value = Color.red (first enum-value)
      class Example2(HasTraits):
          color = UseEnum(Color)
  
      example = Example2()
      self.assertEqual(example.color, Color.red)
  
imports: import unittest
  import enum
  from ipython_genutils.py3compat import string_types
  from traitlets import HasTraits, TraitError, UseEnum
label_desc: Use image node_id 11 for calling the TestUseEnum obj's underlying member method code with example usage: obj.test_ctor_without_default_value() without return types