diff --git a/geomagio/Controller.py b/geomagio/Controller.py
index ce39685fb3e9ab31ec7c13c735afbc0a4d63e823..dce6b9194218bfb0c21bc1fc595999bb55939aa3 100644
--- a/geomagio/Controller.py
+++ b/geomagio/Controller.py
@@ -1031,7 +1031,7 @@ def parse_args(args):
             "temperature",
             "vbf",
             "xml",
-            'covjson',
+            "covjson",
         ),
         # TODO: set default to 'iaga2002'
         help="Output format",