UserField::getFormattedValueForExport

protected function getFormattedValueForExport($fieldValue, int $itemId, Options $displayOptions): string
{
	if (!$this->isMultiple())
	{
		return $this->getPreparedValueForExport($fieldValue);
	}

	$results = [];
	foreach ($fieldValue as $elementId)
	{
		$results[] = $this->getPreparedValueForExport($elementId);
	}

	return implode($displayOptions->getMultipleFieldsDelimiter(), $results);
}