odoo-10

Try with this example: from dateutil.relativedelta import relativedelta @api.one @api.depends(‘start_field’,’finish_field’) def _total_minutes(self): if self.start_field and self.finish_field: start_dt = fields.Datetime.from_string(self.start_field) finish_dt = fields.Datetime.from_string(self.finish_field) difference = relativedelta(finish_dt, start_dt) days = difference.days hours = difference.hours minutes = difference.minutes seconds = 0