diff --git a/lldb/packages/Python/lldbsuite/test/lldbtest.py b/lldb/packages/Python/lldbsuite/test/lldbtest.py
index c8b600b..51e11a7 100644
--- a/lldb/packages/Python/lldbsuite/test/lldbtest.py
+++ b/lldb/packages/Python/lldbsuite/test/lldbtest.py
@@ -619,10 +619,10 @@
 def check_list_or_lambda(list_or_lambda, value):
     if six.callable(list_or_lambda):
         return list_or_lambda(value)
-    elif isinstance(list_or_lambda, list):
-        return list_or_lambda is None or value is None or value in list_or_lambda
+    elif isinstance(list_or_lambda, list) or isinstance(list_or_lambda, str):
+        return value is None or value in list_or_lambda
     else:
-        return list_or_lambda == value
+        return list_or_lambda is None or value is None or list_or_lambda == value
 
 # provide a function to xfail on defined oslist, compiler version, and archs
 # if none is specified for any argument, that argument won't be checked and thus means for all