Remove safe eval

product_oneclick.py

@@ -3,7 +3,7 @@
 # the full copyright notices and license terms.
 from trytond.model import fields
 from trytond.pool import PoolMeta
-from trytond.pyson import Eval, Bool
+from trytond.pyson import Eval, Not, Bool
 from trytond.model.fields import depends
 
 __all__ = ['ProductOneClickView', 'ProductOneClick']
@@ -42,6 +42,13 @@ class ProductOneClickView:
             res['training_registration'] = self.training_start_date
         return res
 
+    @classmethod
+    def view_attributes(cls):
+        return super(ProductOneClickView, cls).view_attributes() + [
+            ('//page[@id="esale"]', 'states', {
+                    'invisible': Not(Bool(Eval('training'))),
+                    })]
+
 
 class ProductOneClick:
     __name__ = 'product.oneclick'

view/product_oneclick_view_form.xml

@@ -8,9 +8,7 @@ The COPYRIGHT file at the top level of this repository contains the full copyrig
         <field name="training"/>
     </xpath>
     <xpath expr="/form/notebook/page[@id='sale']" position="after">
-        <page string="Training"
-            states="{'invisible': Not(Bool(Eval('training')))}"
-            id="training">
+        <page string="Training" id="training">
             <label name="training_start_date"/>
             <field name="training_start_date"/>
             <label name="training_end_date"/>