I get errors testing astshim with pybind11 2.5.
Note that FitsKeyState is an "enum class" type, and includes an export_values() call in the declaration for pybind11.
There is a note in the developer guide about using .export_values with that type, which I'm not sure if it's applicable in this instance, which reads:
Add .export_values() if (and only if) you need to export the values into the class scope (so they can be reached as ExampleOne.RED, in addition to ExampleOne.State.Red).
Never do this for new style scoped enum class types, since that will give them different symantics in C++ and Python.