namespace Utility { export namespace Fees { export function CalculateLateFees(daysLate: number): number { return daysLate * 0.25; } } export function MaxBooksAllowed(age: number): number { if (age < 12) { return 3; } else { return 10; } } // Since it is not exported, it will be private to the namespace. function privateFunc(): void { console.log('This is private...'); } }