  
      def __init__(self, choices=(), *args, **kwargs):
          super(ChoiceField, self).__init__(*args, **kwargs)
          self.choices = choices
  
      def _get_choices(self):
          return self._choices
  
      def _set_choices(self, value):
          # Setting choices also sets the choices on the widget.
 
</s> remove         self.assertEqual(s.errors,  {'decimal_field': ['Ensure that there are no more than 4 digits in total.']}) </s> add  </s> remove     ManyToManyModel, Person, ReadOnlyManyToManyModel, Photo)
 </s> add     ManyToManyModel, Person, ReadOnlyManyToManyModel, Photo, SeveralChoicesModel)
        if not self.required:
            self.choices = BLANK_CHOICE_DASH + self.choices
  
      def __init__(self, choices=(), *args, **kwargs):
          super(ChoiceField, self).__init__(*args, **kwargs)
          self.choices = choices
        if not self.required:
            self.choices = BLANK_CHOICE_DASH + self.choices
  
      def _get_choices(self):
          return self._choices
  
      def _set_choices(self, value):
          # Setting choices also sets the choices on the widget.
keep keep keep add keep keep keep keep keep keep
 Adding `BLANK_CHOICE_DASH` as a choice if the model's field isn't required 
rest_framework/fields.py