Here is a helper class to convert a PHP array to XML
You would call it doing the following:
<?php
$xml = new Xml();
$xml-> generateXmlFromArray($array, 'entities', 'entity');
?>
<?php
class Xml
{
    public function getXmlFromArray($value, \SimpleXMLElement &$xmlElement, $entity, $starting = null)
    {
        $handleValue = function($value){
            if(is_string($value)){
                $value = htmlspecialchars($value);
            }
            return $value;
        };
        $addChild = function($name, $value, &$subNode = null)use(&$xmlElement, $handleValue, $entity){
            if(is_array($value)){
                if(!$subNode instanceof \SimpleXMLElement){
                    $currentKey = key($value);
                    $initialValue = null;
                    if(is_numeric($currentKey)){
                        if(!is_array($value[$currentKey])){
                            $initialValue = $value[$currentKey];
                            unset($value[$currentKey]);
                        }
                    }
                    $subNode = $xmlElement->addChild($name, $initialValue);
                }
                $this->getXmlFromArray($handleValue($value), $subNode, $name);
            } else {
                $xmlElement->addChild($name, $handleValue($value));
            }
        };
        if(is_array($value))
        {
            if(is_numeric(key($value))){
                $setSubNodePrimitiveValue = function($value)use(&$xmlElement, $entity, $handleValue){
                    $value = $handleValue($value);
                    $children = $xmlElement->children();
                    $children[] = $value;
                };
                foreach ($value as $item)
                {
                    if(!is_array($item)){
                        $setSubNodePrimitiveValue($item);
                    } else {
                        if($starting === true){
                            $addChild($entity, $item);
                        } else {
                            $addChild($entity, $item, $xmlElement);
                        }
                    }
                }
            } else {
                foreach ($value as $subEntity => $subEntityItem)
                {
                    $addChild($subEntity, $subEntityItem);
                }
            }
        } else {
            $xmlElement->addChild($entity, $handleValue($value));
        }
    }
    public function generateXmlFromArray(array $array, string $openingTag, string $entity, $nameSpace = '', $isPrefixed = false)
    {
        $xmlString = '<'.$openingTag.'></'.$openingTag.'>';
        $xml = new \SimpleXMLElement($xmlString, LIBXML_NOERROR, false, $nameSpace, $isPrefixed);
        $this->getXmlFromArray($array, $xml, $entity, true);
        return $xml;
    }
    public function validateXml(string $xml)
    {
        $dom = new \DOMDocument();
        $dom->loadXML($xml);
        return $dom->validate();
    }
    public function loadXmlPathAsArray(string $xmlPath)
    {
        $xml   = simplexml_load_file($xmlPath);
        $array = json_decode(json_encode($xml), TRUE);
        return (array)$array;
    }
    public function loadXmlStringAsArray(string $xmlString)
    {
        $array = (array) @simplexml_load_string($xmlString);
        if(!$array){
            $array = (array) @json_decode($xmlString, true);
        } else{
            $array = (array)@json_decode(json_encode($array), true);
        }
        return $array;
    }
    public function loadXmlString(string $xmlString)
    {
        return @simplexml_load_string($xmlString);
    }
}
?>