Merge branch 'master' into v4_integration

Author: jonmmease

packages/python/plotly/plotly/offline/offline.py

@@ -166,7 +166,8 @@ def _get_jconfig(config=None):
 
     plotly_platform_url = plotly.tools.get_config_plotly_server_url()
 
-    clean_config["plotlyServerURL"] = plotly_platform_url
+    if not clean_config.get("plotlyServerURL", None):
+        clean_config["plotlyServerURL"] = plotly_platform_url
 
     if (
         plotly_platform_url != "https://plot.ly"