diff --git a/dynamic_beast/main.py b/dynamic_beast/main.py
index 43e6a3d..067fd80 100644
--- a/dynamic_beast/main.py
+++ b/dynamic_beast/main.py
@@ -89,11 +89,11 @@ def add_ns_options(run):
         "particleCount": "1",
         "subChainLength": "5000",
         "epsilon": "1e-12",
-        "stopFactor": '2.0',
+        "stopFactor": "2.0",
         "minSteps": "0",
         "autoSubChainLength": "false",
         "paramCountFactor": "10",
-        "producePosterior": "true"
+        "producePosterior": "true",
     }
     for option in ns_options:
         run.set(option, ns_options[option])