Description:
------------
---
From manual page: https://php.net/datetime.createfromformat
---
On the page the format option 'v' is not documented:
(It takes the milliseconds)

Test script:
---------------

$dates = [
	'short' => '20201112132455999',
	'long' =>  '20201112132455999888'
];

$formats=[
	'u' => 'YmdHisu',
	'v' => 'YmdHisv'
];


foreach ($dates as $dk => $d)
	foreach ($formats as $f ){
	 $v = DateTime::createFromFormat($f,$d);
	 echo "result for ".$d." with format ".$f.' is: ';
	 print_r( !is_a($v,'DateTime')? ['not-a-datetime'] : $v);
	}

Expected result:
----------------
result for (short) 20201112132455999 with format YmdHisu is: DateTime Object
(
    [date] => 2020-11-12 13:24:55.999000
    [timezone_type] => 3
    [timezone] => UTC
)
result for (short) 20201112132455999 with format YmdHisv is: DateTime Object
(
    [date] => 2020-11-12 13:24:55.999000
    [timezone_type] => 3
    [timezone] => UTC
)
result for (long) 20201112132455999888 with format YmdHisu is: DateTime Object
(
    [date] => 2020-11-12 13:24:55.999888
    [timezone_type] => 3
    [timezone] => UTC
)
result for (long) 20201112132455999888 with format YmdHisv is: Array
(
    [0] => not-a-datetime
)