PrettyPrinter::formatUserFieldAsDate

static function formatUserFieldAsDate($userField, $value, $format)
{
	if ($userField['MULTIPLE'] == 'Y')
	{
		if ($value)
		{
			$values = unserialize($value, ['allowed_classes' => static::$allowedUnserializeClassesList]);
			if (is_array($values))
			{
				foreach ($values as $i => &$v)
				{
					if (is_object($v) && is_a($v, 'BitrixMainTypeDate'))
					{
						$v = $v->format($format);
					}
					elseif (is_string($v))
					{
						$date = BitrixMainTypeDateTime::createFromTimestamp(strtotime($v));
						$v = $date->format($format);
					}
					else
					{
						unset($values[$i]);
					}
				}
				unset($v);

				return implode(', ', $values);
			}
		}
		return '';
	}
	elseif ($value)
	{
		if (is_object($value) && is_a($value, 'BitrixMainTypeDate'))
		{
			return $value->format($format);
		}
		elseif (is_string($value))
		{
			$date = BitrixMainTypeDateTime::createFromTimestamp(strtotime($value));

			return $date->format($format);
		}
	}

	return '';
}