Keep shop is defined

sale.py

@@ -25,8 +25,14 @@ class Sale(metaclass=PoolMeta):
         Shop = Pool().get('sale.shop')
         Product = Pool().get('product.product')
         Party = Pool().get('party.party')
-        shop_id = ctx['shop']
-        shop = Shop(shop_id)
+        User = Pool().get('res.user')
+        if ctx.get('shop'):
+            shop = Shop(ctx['shop'])
+        else:
+            user_id = ctx.get('user')
+            user = User(user_id)
+            shop = user.shop
+
         today = date.today()
         for v in args['lines']:
             del v['id']
@@ -35,6 +41,7 @@ class Sale(metaclass=PoolMeta):
             product = Product(v['product'])
             v['unit'] = product.template.default_uom.id
             v['description'] = product.name
+
         price_list = args.get('price_list', None)
         if price_list:
             price_list = price_list['id']
@@ -50,7 +57,7 @@ class Sale(metaclass=PoolMeta):
             agent_id = args['agent']['id']
 
         to_create = {
-            'shop': shop_id,
+            'shop': shop.id,
             'invoice_type': 'P',
             'company': shop.company.id,
             'party': args['party']['id'],