diff --git a/__init__.py b/__init__.py
index 2b370ceceb..f7b292bc36 100644
--- a/__init__.py
+++ b/__init__.py
@@ -1,4 +1,11 @@
 #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 .purchase_request import *
+
+
+def register():
+    Pool.register(
+        PurchaseRequest,
+        module='stock_supply_forecast', type_='model')
diff --git a/purchase_request.py b/purchase_request.py
index 209a25c110..05966f63d2 100644
--- a/purchase_request.py
+++ b/purchase_request.py
@@ -1,24 +1,26 @@
 #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.model import Model
-from trytond.pool import Pool
+from trytond.pool import Pool, PoolMeta
+
+__all__ = ['PurchaseRequest']
+__metaclass__ = PoolMeta
 
 
-class PurchaseRequest(Model):
-    _name = 'purchase.request'
+class PurchaseRequest:
+    __name__ = 'purchase.request'
 
-    def generate_requests(self):
-        forecast_obj = Pool().get('stock.forecast')
-        date_obj = Pool().get('ir.date')
+    @classmethod
+    def generate_requests(cls):
+        pool = Pool()
+        Forecast = pool.get('stock.forecast')
+        Date = pool.get('ir.date')
 
-        today = date_obj.today()
+        today = Date.today()
 
-        forecast_ids = forecast_obj.search([
+        forecasts = Forecast.search([
                 ('to_date', '>=', today),
                 ('state', '=', 'done'),
                 ])
-        forecast_obj.create_moves(forecast_ids)
-        super(PurchaseRequest, self).generate_requests()
-        forecast_obj.delete_moves(forecast_ids)
-
-PurchaseRequest()
+        Forecast.create_moves(forecasts)
+        super(PurchaseRequest, cls).generate_requests()
+        Forecast.delete_moves(forecasts)