'Returns Finnish VAT identification number (Arvonlisaveronumero).
This can be calculated from company business identity code by
adding prefix "FI" and removing dash before checksum.'

def company_vat(self):

    def convert_to_vat(business_id):
        u'\n                                                Convert    business    id    to    VATIN\n                                                '
        return (u'FI' + business_id.replace(u'-', u''))
    return convert_to_vat(self.company_business_id())
