move a user more UserAnswer features to base class

generic/models.py

@@ -410,6 +410,11 @@ class UserAnswerBase(models.Model):
         abstract = True
         ordering = ["cid"]
 
+
+    def __str__(self) -> str:
+        return "{}/{}/{}".format(self.get_candidate_name(), self.exam, self.question.pk)
+
+
     def get_candidate_name(self) -> str:
         if self.cid is not None:
             return str(self.cid)
@@ -422,6 +427,9 @@ class UserAnswerBase(models.Model):
         else:
             return str(self.user.id)
 
+    def get_absolute_url(self):
+        return reverse(f"{self.app_name}:user_answer_view", kwargs={"pk": self.pk})
+
 class NoteType(models.Model):
     note_type = models.CharField(max_length=200)