/**
* Sets the distance matrix request unit system.
*
* @param string $unitSystem The distance matrix request unit system.
*
* @throws \Ivory\GoogleMap\Exception\DistanceMatrixException If the unit system is not valid.
*/
public function setUnitSystem($unitSystem = null)
{
if (!in_array($unitSystem, UnitSystem::getUnitSystems()) && $unitSystem !== null) {
throw DistanceMatrixException::invalidDistanceMatrixRequestUnitSystem();
}
$this->unitSystem = $unitSystem;
}
