              (87, 'Core'),
              (22, 'Pear')))
  
          form = InventoryForm(instance=core)
          self.assertHTMLEqual(six.text_type(form['parent']), '''<select name="parent" id="id_parent">
  <option value="">---------</option>
  <option value="86" selected>Apple</option>
  <option value="87">Core</option>
  <option value="22">Pear</option>
  </select>''')
 
</s> remove             six.text_type(f),
 </s> add             str(f), </s> remove         self.assertIn('name="myfile"', six.text_type(form))
        self.assertNotIn('myfile-clear', six.text_type(form))
 </s> add         self.assertIn('name="myfile"', str(form))
        self.assertNotIn('myfile-clear', str(form)) </s> remove         self.assertIn('myfile-clear', six.text_type(form))
 </s> add         self.assertIn('myfile-clear', str(form)) </s> remove         self.assertEqual(six.text_type(instance), 'Bob Woodward is 65')
 </s> add         self.assertEqual(str(instance), 'Bob Woodward is 65') </s> remove             'writer': six.text_type(self.w_woodward.pk),
 </s> add             'writer': str(self.w_woodward.pk),
        self.assertHTMLEqual(str(form['parent']), '''<select name="parent" id="id_parent">
              (87, 'Core'),
              (22, 'Pear')))
  
          form = InventoryForm(instance=core)
        self.assertHTMLEqual(str(form['parent']), '''<select name="parent" id="id_parent">
  <option value="">---------</option>
  <option value="86" selected>Apple</option>
  <option value="87">Core</option>
  <option value="22">Pear</option>
  </select>''')
keep keep keep keep replace keep keep keep keep keep
 Refs #23919 -- Removed six.<various>_types usage

Thanks Tim Graham and Simon Charette for the reviews. 
tests/model_forms/tests.py