hi ,

i want to compute length of list by function and store  result  in the empty field  , i have done this but it isnt working

count_line = fields.Integer('Result')

    @api.multi
    def on_change_lines_ids(self,line_ids):
        if line_ids :
                for line in line_ids :
                    x = len(line_ids)
                    self.count_line = x
                raise except_orm(_('Bien fait !'))

thanks to help me