Use Assert lib for value checking in setters

src/Entity/Company.php

@@ -150,6 +150,8 @@ abstract class Company extends StructuralDBElement
     /**
      * Set the addres
      * @param string $new_address       the new address (with "\n" as line break)
+     *
+     * @return self
      */
     public function setAddress(string $new_address) : self
     {
@@ -161,6 +163,8 @@ abstract class Company extends StructuralDBElement
      * Set the phone number
      *
      * @param string $new_phone_number       the new phone number
+     *
+     * @return self
      */
     public function setPhoneNumber(string $new_phone_number) : self
     {
@@ -172,6 +176,8 @@ abstract class Company extends StructuralDBElement
      * Set the fax number
      *
      * @param string $new_fax_number       the new fax number
+     *
+     * @return self
      */
     public function setFaxNumber(string $new_fax_number) : self
     {
@@ -183,6 +189,8 @@ abstract class Company extends StructuralDBElement
      * Set the e-mail address
      *
      * @param string $new_email_address       the new e-mail address
+     *
+     * @return self
 
      */
     public function setEmailAddress(string $new_email_address) : self
@@ -195,6 +203,8 @@ abstract class Company extends StructuralDBElement
      * Set the website
      *
      * @param string $new_website       the new website
+     *
+     * @return self
      */
     public function setWebsite(string $new_website) : self
     {
@@ -207,6 +217,7 @@ abstract class Company extends StructuralDBElement
      *
      * @param string $new_url       the new URL with the placeholder %PARTNUMBER% for the part number
      *
+     * @return self
      */
     public function setAutoProductUrl(string $new_url) : self
     {