The method description looks like it requires a parameter, but it is actually optional:
$iter= new ArrayIterator();
$iter['bacon'] = 'tasty';
(PHP 5 >= 5.0.0, PHP 7)
ArrayIterator::__construct — Construct an ArrayIterator
Constructs an ArrayIterator object.
This function is currently not documented; only its argument list is available.
arrayThe array or object to be iterated on.
flagsFlags to control the behaviour of the ArrayIterator object. See ArrayIterator::setFlags().
An ArrayIterator object.
ArrayIterator::__construct() throws an InvalidArgumentException if anything besides an array or an object is given.
The method description looks like it requires a parameter, but it is actually optional:
$iter= new ArrayIterator();
$iter['bacon'] = 'tasty';