Use tryton.cfg to register in the Pool

modules/purchase_requisition/__init__.py

@@ -1,21 +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 ir, purchase
-
-
-def register():
-    Pool.register(
-        ir.Rule,
-        purchase.PurchaseRequest,
-        purchase.PurchaseRequisition,
-        purchase.PurchaseRequisitionLine,
-        purchase.Configuration,
-        purchase.ConfigurationSequence,
-        module='purchase_requisition', type_='model')
-    Pool.register(
-        purchase.HandlePurchaseCancellationException,
-        purchase.CreatePurchase,
-        module='purchase_requisition', type_='wizard')

modules/purchase_requisition/tryton.cfg

@@ -11,3 +11,15 @@ depends:
 xml:
     purchase.xml
     message.xml
+
+[register]
+model:
+    ir.Rule
+    purchase.Configuration
+    purchase.ConfigurationSequence
+    purchase.PurchaseRequest
+    purchase.PurchaseRequisition
+    purchase.PurchaseRequisitionLine
+wizard:
+    purchase.HandlePurchaseCancellationException
+    purchase.CreatePurchase