old_contents: from openerp import fields, models
  
  
  class ir_actions_todo(models.Model):
      _inherit = 'ir.actions.todo'
  
  
      repeat = fields.Boolean(string='Repeat')
  
  
      _defaults = {
          'repeat': False,
      }
  
      def action_launch(self, cr, uid, ids, context=None):
          res = super(ir_actions_todo, self).action_launch(cr, uid, ids, context)
          wizard_id = ids and ids[0] or False
          wizard = self.browse(cr, uid, wizard_id, context=context)
          if wizard.type in ('automatic', 'once') and wizard.repeat:
              wizard.write({'state': 'open'})
          return res
  
new_contents: from openerp import fields, models, api
  
  
  class ir_actions_todo(models.Model):
      _inherit = 'ir.actions.todo'
  
      repeat = fields.Boolean(string='Repeat', repeat=False)
  
      @api.multi
      def action_launch(self, context=None):
          res = super(ir_actions_todo, self).action_launch(context=context)
          for wizard in self:
              if wizard.type in ('automatic', 'once') and wizard.repeat:
                  wizard.write({'state': 'open'})
          return res
  
subject: update to new api