docs: def get_previous_and_current_values(self, instance):
          """
          Obtain the previous and actual values and compares them
          in order to detect which fields has changed
  
          :param instance:
          :param translation:
          :return:
          """
          translated_field_names = self._get_translated_field_names(instance.master)
          if instance.pk:
              try:
                  previous_obj = instance._meta.model.objects.get(pk=instance.pk)
                  previous_values = self.get_obj_values(previous_obj, translated_field_names)
              except ObjectDoesNotExist:
                  previous_values = {}
          else:
              previous_values = {}
          current_values = self.get_obj_values(instance, translated_field_names)
          return previous_values, current_values