title: Odoo computed field Year from date_invoice
body: <p>How can I extract only the year from a date field (x_date_invoice) to a new computed odoo field for example x_jaar</p>
  
  <p>I am using Odoo 10.
  <a href="https://i.stack.imgur.com/BgThC.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/BgThC.png" alt="FIeld x_jaar info"></a>
  <a href="https://i.stack.imgur.com/sWTNb.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/sWTNb.png" alt="Field x_date_invoice info"></a></p>