diff --git a/.pylintrc b/.pylintrc
index c3044af58..894546021 100644
--- a/.pylintrc
+++ b/.pylintrc
@@ -1,9 +1,8 @@
 [MASTER]
 
-disable=redefined-outer-name,arguments-differ,no-self-use,cyclic-import,fixme,locally-disabled,unpacking-non-sequence,too-many-ancestors,too-many-branches,too-few-public-methods,import-outside-toplevel,bad-continuation
+disable=redefined-outer-name,arguments-differ,no-self-use,cyclic-import,fixme,locally-disabled,too-many-ancestors,too-few-public-methods,import-outside-toplevel,bad-continuation,signature-differs
 load-plugins=pylint_django,pylint.extensions.bad_builtin
 extension-pkg-whitelist=lxml
 const-rgx=[a-zA-Z0-9_]{1,40}$
 ignored-modules=django-otp
 jobs=4
-
diff --git a/passbook/providers/saml/processors/base.py b/passbook/providers/saml/processors/base.py
index c187ebbf8..340249a15 100644
--- a/passbook/providers/saml/processors/base.py
+++ b/passbook/providers/saml/processors/base.py
@@ -195,7 +195,7 @@ class Processor:
         try:
             self._extract_saml_request()
         except KeyError:
-            raise CannotHandleAssertion(f"Couldn't find SAML request in user session")
+            raise CannotHandleAssertion("Couldn't find SAML request in user session")
 
         try:
             self._decode_and_parse_request()