string representation

Starting from Python 3, the __str__ method was introduced as a replacement for __unicode__ to provide a string representation of an object.

django_walletpass/models.py

@@ -285,6 +285,9 @@ def get_pass_builder(self):
     def __unicode__(self):
         return self.serial_number
 
+    def __str__(self):
+        return self.serial_number
+
     class Meta:
         verbose_name_plural = "passes"
         unique_together = (
@@ -308,6 +311,9 @@ class Registration(models.Model):
     def __unicode__(self):
         return self.device_library_identifier
 
+    def __str__(self):
+        return self.device_library_identifier
+
 
 class Log(models.Model):
     """
@@ -317,3 +323,6 @@ class Log(models.Model):
 
     def __unicode__(self):
         return self.message
+
+    def __str__(self):
+        return self.message