Use tryton.cfg to register in the Pool

modules/product_cost_history/__init__.py

@@ -1,16 +1,2 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
-
-from trytond.pool import Pool
-
-from . import product
-
-__all__ = ['register']
-
-
-def register():
-    Pool.register(
-        product.Product,
-        product.CostPrice,
-        product.ProductCostHistory,
-        module='product_cost_history', type_='model')

modules/product_cost_history/tryton.cfg

@@ -6,3 +6,9 @@ depends:
     stock
 xml:
     product.xml
+
+[register]
+model:
+    product.Product
+    product.CostPrice
+    product.ProductCostHistory