Conversion from SingleCellExperiment to AnnData fails to convert `.uns` back to python objects

[scottgigante]

Minimal code sample

import scanpy as sc
import rpy2.robjects as ro
import rpy2.robjects.numpy2ri
import anndata2ri

rpy2.robjects.numpy2ri.activate()
anndata2ri.activate()

pbmc = sc.datasets.pbmc68k_reduced()
ro.globalenv['sce'] = pbmc
pbmc_converted = ro.globalenv['sce']

pbmc_converted.write_h5ad("test.h5ad")

Traceback (most recent call last):
  File "/home/scottgigante/.local/lib/python3.6/site-packages/anndata/_io/utils.py", line 188, in func_wrapper
    return func(elem, key, val, *args, **kwargs)
  File "/home/scottgigante/.local/lib/python3.6/site-packages/anndata/_io/h5ad.py", line 145, in write_not_implemented
    f"Failed to write value for {key}, "
NotImplementedError: Failed to write value for uns/louvain, since a writer for type <class 'rpy2.robjects.vectors.ListVector'> has not been implemented yet.

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/scottgigante/.local/lib/python3.6/site-packages/anndata/_core/anndata.py", line 1852, in write_h5ad
    as_dense=as_dense,
  File "/home/scottgigante/.local/lib/python3.6/site-packages/anndata/_io/h5ad.py", line 112, in write_h5ad
    write_attribute(f, "uns", adata.uns, dataset_kwargs=dataset_kwargs)
  File "/usr/lib/python3.6/functools.py", line 807, in wrapper
    return dispatch(args[0].__class__)(*args, **kw)
  File "/home/scottgigante/.local/lib/python3.6/site-packages/anndata/_io/h5ad.py", line 126, in write_attribute_h5ad
    _write_method(type(value))(f, key, value, *args, **kwargs)
  File "/home/scottgigante/.local/lib/python3.6/site-packages/anndata/_io/h5ad.py", line 286, in write_mapping
    write_attribute(f, f"{key}/{sub_key}", sub_value, dataset_kwargs=dataset_kwargs)
  File "/usr/lib/python3.6/functools.py", line 807, in wrapper
    return dispatch(args[0].__class__)(*args, **kw)
  File "/home/scottgigante/.local/lib/python3.6/site-packages/anndata/_io/h5ad.py", line 126, in write_attribute_h5ad
    _write_method(type(value))(f, key, value, *args, **kwargs)
  File "/home/scottgigante/.local/lib/python3.6/site-packages/anndata/_io/utils.py", line 195, in func_wrapper
    ) from e
NotImplementedError: Failed to write value for uns/louvain, since a writer for type <class 'rpy2.robjects.vectors.ListVector'> has not been implemented yet.

Above error raised while writing key 'uns/louvain' of <class 'h5py._hl.files.File'> from /.

Versions

Details

>>> sc.logging.print_versions()
scanpy==1.4.6 anndata==0.7.3 umap==0.4.6 numpy==1.19.1 scipy==1.5.2 pandas==1.0.5 scikit-learn==0.23.1 statsmodels==0.11.1 python-igraph==0.8.2 louvain==0.6.0
>>> anndata2ri.__version__
'1.0.5.dev2+ea266ab'
>>> rpy2.__version__
'3.3.6'
>>> sys.version_info
sys.version_info(major=3, minor=6, micro=9, releaselevel='final', serial=0)