public function testApply()
{
$sum = function (...$nums) {
return Std::foldl(function ($acc, $value) {
return $acc + $value;
}, 0, $nums);
};
$this->assertEqualsMatrix([[28, Std::apply($sum, [1, 2, 3, 4, 5, 6, 7])], ['hello world', Std::apply(Std::class . '::concat', ['hello ', 'world'])]]);
}