diff --git a/goatools/godag/obo_optional_attributes.py b/goatools/godag/obo_optional_attributes.py
index bc5ba74..b6b53f7 100644
--- a/goatools/godag/obo_optional_attributes.py
+++ b/goatools/godag/obo_optional_attributes.py
@@ -8,6 +8,8 @@
 import re
 import collections as cx
 
+from ..base import logger
+
 
 class OboOptionalAttrs:
     """Manage optional GO-DAG attributes."""
@@ -258,13 +260,14 @@ def get_optional_attrs(optional_attrs, attrs_opt):
         try:
             iter(optional_attrs)
         except TypeError:
-            pat = (
-                "**FATAL: GODag's optional_attrs MUST BE A SET CONTAINING ANY OF: {ATTRS}\n"
+            logger.fatal(
+                "GODag's optional_attrs MUST BE A SET CONTAINING ANY OF: %s\n"
                 "           "
-                "**FATAL: BAD GODag optional_attrs({BADVAL})"
+                "BAD GODag optional_attrs(%s)",
+                " ".join(attrs_opt),
+                optional_attrs,
             )
-            msg = pat.format(ATTRS=" ".join(attrs_opt), BADVAL=optional_attrs)
-            raise TypeError(msg)
+            exit()
         getnm = lambda aopt: aopt if aopt != "defn" else "def"
         opts = None
         if isinstance(optional_attrs, str) and optional_attrs in attrs_opt: