html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/3018#issuecomment-507749287,https://api.github.com/repos/pydata/xarray/issues/3018,507749287,MDEyOklzc3VlQ29tbWVudDUwNzc0OTI4Nw==,2448579,2019-07-02T16:23:57Z,2019-07-02T16:23:57Z,MEMBER,OK looks like the method was added to the `DataArrayGroupBy` class not `GroupBy`. I should've caught this at review. Just moving the function definition to `GroupBy` seems to make things work,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,455262061
https://github.com/pydata/xarray/issues/3018#issuecomment-507743549,https://api.github.com/repos/pydata/xarray/issues/3018,507743549,MDEyOklzc3VlQ29tbWVudDUwNzc0MzU0OQ==,2448579,2019-07-02T16:08:51Z,2019-07-02T16:08:51Z,MEMBER,Well that was an oversight. Any interest in opening a PR @tommylees112 or @huard ,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,455262061
https://github.com/pydata/xarray/issues/3018#issuecomment-507685922,https://api.github.com/repos/pydata/xarray/issues/3018,507685922,MDEyOklzc3VlQ29tbWVudDUwNzY4NTkyMg==,81219,2019-07-02T13:50:27Z,2019-07-02T13:50:27Z,CONTRIBUTOR,"The PR only covered DataArrays, not Datasets, so yes, this is expected. ","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,455262061
https://github.com/pydata/xarray/issues/3018#issuecomment-507630032,https://api.github.com/repos/pydata/xarray/issues/3018,507630032,MDEyOklzc3VlQ29tbWVudDUwNzYzMDAzMg==,21049064,2019-07-02T11:10:33Z,2019-07-02T11:10:33Z,NONE,"This is an awesome addition thankyou!  I updated my `xarray` to V:`0.12.2` but I am still getting an error with dataset objects

```python
a = np.ones((400)) * 10
a[3:7] = 0.2
a[10:13] = 0.2
p = np.repeat(a, 25).reshape(400, 5, 5)
lat = np.arange(0, 5)
lon = np.arange(0, 5)
time = pd.date_range('2000-01-01', freq='M', periods=p.shape[0])
d = xr.Dataset(
    {'precip': (['time', 'lat', 'lon'], p)},
    coords={
        'lon': lon,
        'lat': lat,
        'time': time
    }
)

d.groupby('time.month').quantile(q=0.1)
```

gives the error message
```
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-38-276cfe319286> in <module>
----> 1 d.groupby('time.month').quantile(q=0.1)

AttributeError: 'DatasetGroupBy' object has no attribute 'quantile'
```

Whereas for the `DataArray` it works fine.
```python
d.precip.groupby('time.month').quantile(q=0.1)

Out[39]:
<xarray.DataArray 'precip' (month: 12)>
array([10., 10., 10., 10., 10., 10., 10., 10., 10., 10., 10., 10.])
Coordinates:
  * month    (month) int64 1 2 3 4 5 6 7 8 9 10 11 12
```

Is this the expected behaviour?

```
INSTALLED VERSIONS
------------------
commit: None
python: 3.7.0 | packaged by conda-forge | (default, Nov 12 2018, 12:34:36)
[Clang 4.0.1 (tags/RELEASE_401/final)]
python-bits: 64
OS: Darwin
OS-release: 18.2.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: en_US.UTF-8
LANG: en_US.UTF-8
LOCALE: en_US.UTF-8
libhdf5: 1.10.4
libnetcdf: 4.6.2

xarray: 0.12.2
pandas: 0.24.2
numpy: 1.16.4
scipy: 1.3.0
netCDF4: 1.5.1.2
pydap: None
h5netcdf: None
h5py: 2.9.0
Nio: None
zarr: None
cftime: 1.0.3.4
nc_time_axis: None
PseudonetCDF: None
rasterio: 1.0.17
cfgrib: 0.9.7
iris: None
bottleneck: 1.2.1
dask: 1.2.2
distributed: 1.28.1
matplotlib: 3.1.0
cartopy: 0.17.0
seaborn: 0.9.0
numbagg: None
setuptools: 41.0.1
pip: 19.1
conda: None
pytest: 4.5.0
IPython: 7.1.1
sphinx: 2.0.1
```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,455262061