return also nonexistent email address as (empty) string

Author: Vitexus

src/AbraFlexi/Adresar.php

@@ -43,11 +43,11 @@ class Adresar extends RW implements Document
      *
      * @param string $purpose Purpose - one of Fak|Obj|Nab|Ppt|Skl|Pok
      *
-     * @return null|string email of primary contact or address email or null
+     * @return null|string email of primary contact or address email or empty string
      */
-    public function getNotificationEmailAddress(string $purpose = '')
+    public function getNotificationEmailAddress(string $purpose = ''): string
     {
-        $email = null;
+        $email = '';
         $emailsRaw = $this->getFlexiData(
             $this->getApiURL(),
             ['detail' => 'custom:id,email,kontakty(primarni,email,odesilatFak,odesilatObj,odesilatNab,odesilatPpt,odesilatSkl,odesilatPok)', 'relations' => 'kontakty'],
@@ -213,7 +213,7 @@ public function getEmail(): string
     }
 
     /**
-     * Get Addressbook Item ID.
+     * Get AddressBook Item ID.
      *
      * @return array<string, string>
      */

src/AbraFlexi/Stitek.php

@@ -113,7 +113,7 @@ public static function getAvailableLabels($object)
             $labelsRaw = $object->getColumnsFromAbraFlexi(
                 ['kod', 'nazev'],
                 [$pathToVsb[$evidenceBackup] => true, 'limit' => 0],
-                'nazev',
+                'nazev'
             );
 
             if (\count($labelsRaw)) {

src/AbraFlexi/email.php

@@ -48,9 +48,9 @@ trait email
      * 3. try Document's primary contact mail
      * 4. try Document's any contact mail
      *
-     * @return string
+     * @return string - empty when no usable email address was found
      */
-    public function getEmail()
+    public function getEmail(): string
     {
         if (empty($this->getDataValue('kontaktEmail'))) {
             $addresser = new Adresar($this->getDataValue('firma'), array_merge(['detail' => 'custom:email'], $this->getConnectionOptions()));
@@ -80,7 +80,7 @@ public function getEmail()
      *
      * @return string column divided list of email addresses
      */
-    public function getRecipients(string $purpose = '')
+    public function getRecipients(string $purpose = ''): string
     {
         $recipients = [];