prevent schema error in PX when mapbox token not set (#1705)

nicolaskruchten · jonmmease · commit dec90ad06a8d · 2019-08-06T12:38:22.000-04:00
diff --git a/packages/python/plotly/plotly/express/_core.py b/packages/python/plotly/plotly/express/_core.py
@@ -29,7 +29,7 @@ def __init__(self):
 defaults = PxDefaults()
 del PxDefaults
 
-MAPBOX_TOKEN = ""
+MAPBOX_TOKEN = None
 
 
 def set_mapbox_access_token(token):
