Total fee now updates when a new fee is added

modules/opencase_cases/src/Entity/OCCase.php

@@ -222,6 +222,10 @@ class OCCase extends RevisionableContentEntityBase implements OCCaseInterface
     return $this;
   }
 
+  public function addToTotalFee(float $amountToAdd): void {
+    $this->set('total_fee', $this->total_fee->value + $amountToAdd);
+    $this->save();
+  }
 
   /**
    * {@inheritdoc}