---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-30-62e3bddfeac0> in <module>
      2 ds = xr.Dataset()
      3 ds[0] = xr.DataArray()
----> 4 ds.to_zarr()

/opt/conda/envs/eurodatacube-0.22.3/lib/python3.8/site-packages/xarray/core/dataset.py in to_zarr(self, store, chunk_store, mode, synchronizer, group, encoding, compute, consolidated, append_dim, region)
   1743             encoding = {}
   1744 
-> 1745         return to_zarr(
   1746             self,
   1747             store=store,

/opt/conda/envs/eurodatacube-0.22.3/lib/python3.8/site-packages/xarray/backends/api.py in to_zarr(dataset, store, chunk_store, mode, synchronizer, group, encoding, compute, consolidated, append_dim, region)
   1452 
   1453     # validate Dataset keys, DataArray names, and attr keys/values
-> 1454     _validate_dataset_names(dataset)
   1455     _validate_attrs(dataset)
   1456 

/opt/conda/envs/eurodatacube-0.22.3/lib/python3.8/site-packages/xarray/backends/api.py in _validate_dataset_names(dataset)
    205 
    206     for k in dataset.variables:
--> 207         check_name(k)
    208 
    209 

/opt/conda/envs/eurodatacube-0.22.3/lib/python3.8/site-packages/xarray/backends/api.py in check_name(name)
    198                 )
    199         elif name is not None:
--> 200             raise TypeError(
    201                 f"Invalid name {name!r} for DataArray or Dataset key: "
    202                 "must be either a string or None for serialization to netCDF "

TypeError: Invalid name 0 for DataArray or Dataset key: must be either a string or None for serialization to netCDF files

TypeError: Invalid name 0 for DataArray or Dataset key: must be either a string or None for serialization to zarr files

import xarray as xr
ds = xr.Dataset()
ds[0] = xr.DataArray()
ds.to_zarr()