BUG: `series_generator.create_series_obj()` failing an `isinstance(..., SeriesBase)` check across dependencies

[hcpchris]

As mentioned here, when calling series_generator.create_series_obj(item) with a BarSeries, the isinstance(value, SeriesBase) check is failing for some reason despite item being a BarSeries.

This is likely due to an instance inheritance issue between Highcharts Maps for Python and Highcharts Core for Python, but it is definitely a bug that needs resolution.