In the openerp 7 form view i have button after clicking the button it will be log out.

I tried the below code but logout tag is not working

def action_logout(self, cr, uid, ids, context=None):
return {
          'type': 'ir.actions.client',
          'tag': 'logout',
          }

In the web module web\static\src\js\chrome.js File

The below instance.web.client_actions are available and the tag is working in python file. But logout is not available in the instance.web.client_actions how to make work logout tag in python file?... or After clicking the button how to logout in python?..

instance.web.client_actions.add("action_notify", "instance.web.action_notify");
instance.web.client_actions.add("action_warn", "instance.web.action_warn");
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instance.web.client_actions.add("login", "instance.web.Login");
instance.web.client_actions.add("reload", "instance.web.Reload");