              self.validators.append(MinValueValidator(min_value, message=message))
  
      def to_internal_value(self, data):
          try:
              data = int(str(data))
          except (ValueError, TypeError):
              self.fail('invalid')
          return data
  
      def to_representation(self, value):
 
</s> remove             return self.choice_strings_to_values[str(data)]
 </s> add             return self.choice_strings_to_values[six.text_type(data)] </s> remove         return str(data).strip()
 </s> add         return six.text_type(data).strip() </s> remove             'REQUEST_METHOD': str(method),
 </s> add             'REQUEST_METHOD': six.text_type(method), </s> remove         return str(value)
 </s> add         return six.text_type(value) </s> remove         return str(data)
 </s> add         return six.text_type(data)
            data = int(six.text_type(data))
              self.validators.append(MinValueValidator(min_value, message=message))
  
      def to_internal_value(self, data):
          try:
            data = int(six.text_type(data))
          except (ValueError, TypeError):
              self.fail('invalid')
          return data
  
      def to_representation(self, value):
keep keep keep keep replace keep keep keep keep keep
 Use six.text_type instead of str everywhere 
rest_framework/fields.py