id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,active_lock_reason,draft,pull_request,body,reactions,performed_via_github_app,state_reason,repo,type
600268506,MDU6SXNzdWU2MDAyNjg1MDY=,3974,load_dataset fails when filename is unicode,12728107,closed,0,,,4,2020-04-15T12:42:49Z,2022-05-06T08:13:04Z,2022-05-06T08:13:04Z,NONE,,,,"It seems like xarray does not handle unicode file names. The error is present even if the unicode characters appear in the parent path.


#### MCVE Code Sample

```python
import xarray as xr
import os
xr.Dataset().to_netcdf('caesar.nc')
os.rename('caesar.nc', 'cæsar.nc')
try:
    xr.load_dataset('cæsar.nc')
    print('Success')
except FileNotFoundError:
    print('File not found')
```

#### Expected Output
'Success'

#### Actual Output
'File not found'

#### Problem Description
xarray does not recognize file names with unicode letters


#### Versions

<details><summary>Output of `xr.show_versions()`</summary>

INSTALLED VERSIONS
------------------
commit: None
python: 3.7.7 (default, Mar 23 2020, 23:19:08) [MSC v.1916 64 bit (AMD64)]
python-bits: 64
OS: Windows
OS-release: 10
machine: AMD64
processor: Intel64 Family 6 Model 158 Stepping 9, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None
libhdf5: 1.10.4
libnetcdf: 4.6.1

xarray: 0.15.1
pandas: 1.0.3
numpy: 1.18.1
scipy: 1.4.1
netCDF4: 1.4.2
pydap: None
h5netcdf: None
h5py: 2.10.0
Nio: None
zarr: None
cftime: 1.1.1.1
nc_time_axis: None
PseudoNetCDF: None
rasterio: None
cfgrib: None
iris: None
bottleneck: None
dask: 2.14.0
distributed: 2.14.0
matplotlib: 3.1.0
cartopy: 0.17.0
seaborn: None
numbagg: None
setuptools: 46.1.3.post20200330
pip: 20.0.2
conda: 4.8.3
pytest: 5.4.1
IPython: 7.13.0
sphinx: None

</details>
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