Add ir.message and use UserWarning/UserError

account.py

@@ -3,6 +3,8 @@
 # the full copyright notices and license terms.
 from trytond.model import fields
 from trytond.pool import Pool, PoolMeta
+from trytond.i18n import gettext
+from trytond.exceptions import UserError
 
 __all__ = ['Configuration', 'ConfigurationDefaultAccount', 'AccountTemplate',
     'Account', 'CreateChartAccount', 'CreateChart', 'UpdateChartStart',
@@ -67,15 +69,6 @@ class AccountTemplate(metaclass=PoolMeta):
 class Account(metaclass=PoolMeta):
     __name__ = 'account.account'
 
-    @classmethod
-    def __setup__(cls):
-        super(Account, cls).__setup__()
-        cls._error_messages.update({
-                'invalid_code_digits': ('The number of code digits '
-                    '%(account_digits)d of account "%(account)s" must be '
-                    '%(digits)d.'),
-                })
-
     @classmethod
     def validate(cls, accounts):
         pool = Pool()
@@ -90,12 +83,11 @@ class Account(metaclass=PoolMeta):
         # Only the first item of code is checked: "570000 (1)" -> "570000"
         code = self.code.split(' ')[0]
         if self.kind != 'view' and len(code) != digits:
-            self.raise_user_error('invalid_code_digits', error_args={
-                    'account_digits': len(code),
-                    'account': self.rec_name,
-                    'digits': digits,
-                    })
-
+            raise UserError(gettext(
+                'account_code_digits.invalid_code_digits',
+                    account_digits=len(code),
+                    account=self.rec_name,
+                    digits=digits))
 
 class CreateChartAccount(metaclass=PoolMeta):
     __name__ = 'account.create_chart.account'

message.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<tryton>
+    <data group="1">
+      <record model="ir.message" id="invalid_code_digits">
+          <field name="text">The number of code digits %(account_digits)d of account "%(account)s" must be %(digits)d.</field>
+      </record>
+    </data>
+</tryton>

tryton.cfg

@@ -6,3 +6,4 @@ depends:
     account
 xml:
     account.xml
+    message.xml