update sams_app.py _get_attr to print value of attrString in exception

sams_classes/sams_app.py

@@ -66,7 +66,7 @@ class SAMSApp:
       pass
     attrList = attrString.split('.')
     if len(attrList) <= 1:
-      raise FunctionNotExists('The function ' + attrString + ' does not exist')
+      raise FunctionNotExists(('The function ' + attrString + ' does not exist'))
     return SAMSApp._get_attr(getattr(thing, attrList[0]), '.'.join(attrList[1:]))
   
   @property