public function testPrepend()
{
$p1 = P::prepend(1);
$this->assertEquals([1, 2, 3], P::toArray(P::prepend(1, [2, 3])));
$this->assertEquals([[1], 2, 3], P::toArray(P::prepend([1], [2, 3])));
$this->assertEquals([1, 2, 3], P::toArray($p1([2, 3])));
$a = function () {
(yield 2);
(yield 3);
};
$this->assertEquals([1, 2, 3], P::toArray(P::prepend(1, $a())));
}