/**
* Returns an array of country names sorted in descending order by population
*
* @param {object[]} arr - The input array. Objects will be in the form: { country: "foo", population: 10 }
* @returns {string[]} - Returns an array of country names, sorted by their population in descending order
*
*/
function getCountriesSortedByPopulation() {
}
module.exports = getCountriesSortedByPopulation