Hi,

i created a button with function error wich watch an error message , but nothing appear

Odoo8 

this is my function 

 def error(self, cr, uid, ids, context=None):

return {'warning':{'title':'warning','message':'Your message'}} 

code xml 

< button colspan="2" name="error" type="action" string="Chercher client" class="oe_link oe_edit_only"/>