          data = {
              'usersite_set-TOTAL_FORMS': '1',
              'usersite_set-INITIAL_FORMS': '1',
              'usersite_set-MAX_NUM_FORMS': '0',
              'usersite_set-0-id': six.text_type(usersite[0]['id']),
              'usersite_set-0-data': '11',
              'usersite_set-0-user': 'apollo13'
          }
          form_set = FormSet(data, instance=user)
          if form_set.is_valid():
 
</s> remove             'usersite_set-0-id': six.text_type(usersite[0]['id']),
 </s> add             'usersite_set-0-id': str(usersite[0]['id']), </s> remove             'usersite_set-0-id': six.text_type(us.pk),
 </s> add             'usersite_set-0-id': str(us.pk), </s> remove             'usersite_set-0-id': six.text_type(us.pk),
 </s> add             'usersite_set-0-id': str(us.pk), </s> remove             'manager_set-0-id': six.text_type(manager[0]['id']),
 </s> add             'manager_set-0-id': str(manager[0]['id']), </s> remove             'manager_set-0-id': six.text_type(manager[0]['id']),
 </s> add             'manager_set-0-id': str(manager[0]['id']),
            'usersite_set-0-id': str(usersite[0]['id']),
          data = {
              'usersite_set-TOTAL_FORMS': '1',
              'usersite_set-INITIAL_FORMS': '1',
              'usersite_set-MAX_NUM_FORMS': '0',
            'usersite_set-0-id': str(usersite[0]['id']),
              'usersite_set-0-data': '11',
              'usersite_set-0-user': 'apollo13'
          }
          form_set = FormSet(data, instance=user)
          if form_set.is_valid():
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_formsets_regress/tests.py