issue_comments: 1287768499

@dcherian cumsum for resample fails for some reason do you have any ideas?

```python import numpy as np import pandas as pd import xarray as xr da = xr.DataArray( np.array([1, 2, 3, 1, 2, np.nan]), dims="time", coords=dict( time=("time", pd.date_range("01-01-2001", freq="M", periods=6)), labels=("time", np.array(["a", "b", "c", "c", "b", "a"])), ), ) ds = xr.Dataset(dict(da=da)) a = ds.resample(time="3M") a.cumsum()

Traceback (most recent call last):

File "C:\Users\J.W\anaconda3\envs\xarray-tests\lib\site-packages\spyder_kernels\py3compat.py", line 356, in compat_exec exec(code, globals, locals)

File "c:\users\j.w\documents\github\xarray\xarray\util\untitled2.py", line 20, in <module> a.cumsum()

File "C:\Users\J.W\Documents\GitHub\xarray\xarray\core_aggregations.py", line 4921, in cumsum return self.reduce(

File "C:\Users\J.W\Documents\GitHub\xarray\xarray\core\resample.py", line 395, in reduce return super().reduce(

File "C:\Users\J.W\Documents\GitHub\xarray\xarray\core\groupby.py", line 1357, in reduce return self.map(reduce_dataset)

File "C:\Users\J.W\Documents\GitHub\xarray\xarray\core\resample.py", line 342, in map return combined.rename({self._resample_dim: self._dim})

File "C:\Users\J.W\Documents\GitHub\xarray\xarray\core\dataset.py", line 3646, in rename return self._rename(name_dict=name_dict, **names)

File "C:\Users\J.W\Documents\GitHub\xarray\xarray\core\dataset.py", line 3587, in _rename raise ValueError(

ValueError: cannot rename 'resample_dim' because it is not a variable or dimension in this dataset ```