and here is the helper

InvenTree/InvenTree/helpers.py

@@ -667,3 +667,18 @@ def clean_decimal(number):
         return Decimal(0)
 
     return clean_number.quantize(Decimal(1)) if clean_number == clean_number.to_integral() else clean_number.normalize()
+
+
+def inheritors(cls):
+    """
+    Return all classes that are subclasses from the supplied cls
+    """
+    subcls = set()
+    work = [cls]
+    while work:
+        parent = work.pop()
+        for child in parent.__subclasses__():
+            if child not in subcls:
+                subcls.add(child)
+                work.append(child)
+    return subcls