Undefined method CRM_Contact_BAO_Relationship::legacyCreateMultiple()

Submitting an application with an Organization results in:

Uncaught Error: Call to undefined method CRM_Contact_BAO_Relationship::legacyCreateMultiple()
in /wp-content/uploads/civicrm/ext/biz.jmaconsulting.grantapplications/CRM/Grant/Form/Grant/Confirm.php:724

CRM_Contact_BAO_Relationship::legacyCreateMultiple() was removed from Core on Nov 29, 2022 (#25048) after being deprecated for quite some time. This was also discussed in question 45092 on civicrm.stackexchange.

Changing

CRM_Contact_BAO_Relationship::legacyCreateMultiple($relParams, $cid);

to

CRM_Contact_BAO_Relationship::createMultiple($relParams, $cid);

seems to work for me.

I do not know if the createMultiple() misses anything from the old legacyCreateMultiple() but the application is saved.

I am also using #191 / !204 and #198 / !203

Patch coming.