'Returns the issued total as will be displayed on partner view'

@api.multi
def _compute_issued_total(self):

    today = fields.Date.context_today(self)
    domain = self.get_followup_lines_domain(today, overdue_only=True)
    for aml in self.env['account.move.line'].search(domain):
        aml.partner_id.issued_total += aml.amount_residual
