““tax-exempt income” means income of a taxpayer from a source in a particular country in respect of which(a) the taxpayer is, under a comprehensive agreement or convention for the elimination of double taxation on income, which has the force of law in the particular country and to which a country in which the taxpayer is resident is a party, entitled to an exemption from all income or profits taxes, imposed in the particular country, to which the agreement or convention applies; and
(b) no income or profits tax to which the agreement or convention does not apply is imposed in the particular country;”;