diff --git a/src/crypto/crl.c b/src/crypto/crl.c
index c90cbe8..025df50 100644
--- a/src/crypto/crl.c
+++ b/src/crypto/crl.c
@@ -162,7 +162,7 @@
 
             default:
                 PyErr_SetString(PyExc_ValueError,
-                        "type argument must be FILETYPE_PEM or FILETYPE_ASN1");
+                        "type argument must be FILETYPE_PEM, FILETYPE_ASN1, or FILETYPE_TEXT");
                 return NULL;
         };
         if( ! ret )