PHP5 Type Hinting - see https://gist.github.com/deshack/e63358a8726b7c3e0ba13563e4f9864c for a full collection of examples about PHP5/PHP7 type hinting

php5-type-hinting.php

<?php

function setOptions(array $options) {
	var_dump($options);
}

setOptions(array());
// array(0) {
// }

setOptions('foo');
// PHP Warning:  Uncaught TypeError: Argument 1 passed to setOptions() must be of the type array, string given

function setValue(string $value) {
	var_dump($value);
}

setValue('foo');
// PHP Catchable fatal error:  Argument 1 passed to setValue() must be an instance of string, string given