PHP: Is The Sun Up (standalone version)?

isSunSup.php

<?php
	
function sunIsUp(\DateTime $when, $lat, $lon): bool {
	$whenTimestamp = $when->getTimestamp();
	
	$sunriseTimestamp = date_sunrise(
		$whenTimestamp,
		SUNFUNCS_RET_TIMESTAMP,
		$lat,
		$lon
	);
	
	$sunsetTimestamp = date_sunset(
		$whenTimestamp,
		SUNFUNCS_RET_TIMESTAMP,
		$lat,
		$lon
	);
	
	return ($whenTimestamp > $sunriseTimestamp) && ($whenTimestamp < $sunsetTimestamp);
}

isSunUpUsage.php

<?php

// Verify sunIsUp functionality using location of Brussels, Belgium.
// On 2018-11-15, sunrise should be at 08:00 and sunset at 16:56
$lat = 50.8503;
$lon = 4.3517;

var_dump(sunIsUp(new \DateTime('2018-11-15 07:15:00', new \DateTimeZone('Europe/Brussels')), $lat, $lon)); // false
var_dump(sunIsUp(new \DateTime('2018-11-15 07:59:00', new \DateTimeZone('Europe/Brussels')), $lat, $lon)); // false
var_dump(sunIsUp(new \DateTime('2018-11-15 08:00:00', new \DateTimeZone('Europe/Brussels')), $lat, $lon)); // true
var_dump(sunIsUp(new \DateTime('2018-11-15 09:15:00', new \DateTimeZone('Europe/Brussels')), $lat, $lon)); // true

var_dump(sunIsUp(new \DateTime('2018-11-15 16:15:00', new \DateTimeZone('Europe/Brussels')), $lat, $lon)); // true
var_dump(sunIsUp(new \DateTime('2018-11-15 16:55:00', new \DateTimeZone('Europe/Brussels')), $lat, $lon)); // true
var_dump(sunIsUp(new \DateTime('2018-11-15 16:56:00', new \DateTimeZone('Europe/Brussels')), $lat, $lon)); // false
var_dump(sunIsUp(new \DateTime('2018-11-15 17:15:00', new \DateTimeZone('Europe/Brussels')), $lat, $lon)); // false