Refactored model and dao

app/models.py

@@ -254,11 +254,11 @@ class InboundNumber(db.Model):
     created_at = db.Column(db.DateTime, default=datetime.datetime.utcnow, nullable=False)
 
     def serialize(self):
-        serialized = {
+        return {
             "id": str(self.id),
             "number": self.number,
             "provider": self.provider,
-            "service_id": self.service_id,
+            "service_id": str(self.service_id),
             "active": self.active,
             "created_at": self.created_at.strftime(DATETIME_FORMAT),
         }