make error messages more helpful when choropleth features and data don't match

I teach a class for students that are new to coding. We use plotly, and I'm happy to have a package that gets students good-looking graphs in so little code.

I introduce plotly's choropleth maps, and have repeatedly run into the issue where the students get confused by what the featureidkey is referring to and how that relates to the locations. I do my best to explain this, but they are (understandably) confused working across CSVs and GeoJSON. One student just hit an issue where they were trying to use FIPS codes, but their locations column had leading whitespace. When the rows are unable to be matched to a feature, it fails silently.

My feature request is to provide a warning when the featureidkey and locations have zero matches.

I haven't contributed to the plotly codebase before, but I'd be open to doing so if the maintainers are open to receiving this. Presumably the place to add this check is one of the validators?

Thanks!

从 packages/python/plotly/plotly/validators/choropleth 开始，issue 将其标识为可能进行检查的位置。使用 GeoJSON feature 标识符和没有匹配项的 locations 重现一个 choropleth，其中包括 FIPS 代码中的前导空白。完成标准是：零匹配的情况会产生清晰的警告，而不是静默失败。