diff --git a/af_benchmark/uproot_processor.py b/af_benchmark/uproot_processor.py
index da4f911..622634d 100644
--- a/af_benchmark/uproot_processor.py
+++ b/af_benchmark/uproot_processor.py
@@ -55,7 +55,7 @@ def get_column_list(self, file):
 
     @tp.enable
     def run_processor(self, files, executor, **kwargs):
-        parallelize_over = self.config.get('processor.parallelize_over', 'files'),
+        parallelize_over = self.config.get('processor.parallelize_over', 'files')
 
         arg_dict = {
             "files": files,