Assert::expectIntegerPositive

static function expectIntegerPositive($arg, $argName = '', $customMsg = '')
{
	$argInt = intval($arg);
	if(((string) $arg !== (string) $argInt) || $argInt <= 0)
		throw new MainArgumentException(self::formMessage('TASKS_ASSERT_INTEGER_NOTNULL_EXPECTED', $argName, $customMsg));

	return $argInt;
}