if i set the basemap in the webmap to 100% transparent then my webmap would not have a basemap shown by default. I want to rely on the default basemap being in the webmap, as a webmap structure has a basemap layer. no matter what's in a webmap, the documentation tells me there's a setBasemap() method that seeks to do exactly that. I'm not interested in workarounds. I need a confirmation that this is either a bug because, for some reason, with this particular type of webmap or its contents, the method does not perform as advertised, or if the basemap service or webmap has been set up wrong such that it causes the method to falter.