improved error handling

backend/utils.py

@@ -41,10 +41,11 @@ def get_item_by_uuid(db: Session, item_uuid: UUID4):
 
 def get_storage_by_name(db: Session, storage_name: str):
     storage = db.get(models.Storage, storage_name)
+    if storage:
         storage.items = [
             item for item in storage.items if item.deployed_at == None  # noqa: E711
         ]
-    return db.get(models.Storage, storage_name)
+    return storage
 
 
 def get_storages(db: Session):
@@ -58,22 +59,24 @@ def get_storages(db: Session):
 
 def get_delivery_by_uuid(db: Session, delivery_uuid: UUID4):
     delivery = db.get(models.Delivery, delivery_uuid)
+    if delivery:
         delivery.amount = len(delivery.items)
         delivery.items = [
             item for item in delivery.items if item.deployed_at == None  # noqa: E711
         ]
-    return db.get(models.Delivery, delivery_uuid)
+    return delivery
 
 
 def get_delivery_by_tag(db: Session, delivery_tag: str):
     delivery = (
         db.query(models.Delivery).filter(models.Delivery.tag == delivery_tag).first()
     )
+    if delivery:
         delivery.amount = len(delivery.items)
         delivery.items = [
             item for item in delivery.items if item.deployed_at == None  # noqa: E711
         ]
-    return db.query(models.Delivery).filter(models.Delivery.tag == delivery_tag).first()
+    return delivery
 
 
 def prepare_delivery(db: Session, verification: str):
@@ -91,6 +94,7 @@ def update_delivery_data(
     db: Session, delivery_uuid: UUID4, update_data: schemas.DeliveryUpdate
 ):
     delivery = db.get(models.Delivery, delivery_uuid)
+    if delivery:
         if update_data.addressee:
             delivery.addressee = escape(update_data.addressee)
         if update_data.team: