InvalidExpression errors when generating stubs for functions with default attributes

[alfonsoSR]

Hi!

I am using pybind11-stubgen to produce stubs for my library, and I have been stuck for a while with this list of warnings

pybind11_stubgen - [WARNING] Enum-like str representations were found with no matching mapping to the enum class location.
Use `--enum-class-locations` to specify full path to the following enum(s):
 - IntegratedObservationPropertyHandling
 - IAUConventions
 - MinimumIntegrationTimeStepHandling
 - LightTimeFailureHandling
 - AerodynamicCoefficientFrames
 ... [goes on with more types]

The common thing I see between all of these enums is that they are used as default value of an argument of some function, and they are always associated with an InvalidExpression error. This is a snippet of code that results into one of these warnings

py::enum_< tom::TroposphericMappingModel >( m, "TroposphericMappingModel", R"doc(No documentation found.)doc" )
        .value( "simplified_chao", tom::TroposphericMappingModel::simplified_chao )
        .value( "niell", tom::TroposphericMappingModel::niell )
        .value( "vmf3", tom::TroposphericMappingModel::vmf3 )
        .export_values( );

m.def( "dsn_tabulated_tropospheric_light_time_correction",
           &tom::tabulatedTroposphericCorrectionSettings,
           py::arg( "file_names" ),
           py::arg( "body_with_atmosphere_name" ) = "Earth",
           py::arg( "mapping_model" ) = tom::TroposphericMappingModel::niell,
           R"doc(No documentation found.)doc" );

I have been trying to look for similar discussions or documentation on the internet, but I haven't found anything. I would like to know what is the reason for these InvalidExpression errors, so that we can adapt the codebase and remove them.