Hi,
after the update from 2.1.0 to 2.1.2 I am getting errors for some Polygons when I try to access the __geo_interface__:
Unexpected error: Unable to find a ring sample point
I guess it is related to 2d207e2

It might be related to holes in the Polygon, but I couldn't figure out why for some there is an error and for some there is no problem.

I create the polygons using the Shapely package. Here is a shapefile containing one example Polygon that fails: poly_fail.zip

Maybe this helps you finding the problem!

Thank you for providing this great tool!