I have a dataset that looks like this (+ some other cols):

```
Value         Theme       Country
-1.975767     Weather     China
-0.540979     Fruits      China
-2.359127     Fruits      China
-2.815604     Corona      Brazil
-0.929755     Weather     UK
-0.929755     Weather     UK

```

I want to find standard deviations for the values after grouping by Themes and Countries (as explained here [calculate standard deviation by grouping two columns](https://stackoverflow.com/questions/71080234/calculate-standard-deviation-by-grouping-two-columns/71080528#71080528)

```
df = pd.read_csv('./Brazil.csv')
df['std'] = df.groupby(['themes', 'country'])['value'].std()

```

However, currently, I get this error:

```
File /usr/local/Cellar/ipython/8.0.1/libexec/lib/python3.10/site-packages/pandas/core/frame.py:3656, in DataFrame.__setitem__(self, key, value)
   3653     self._setitem_array([key], value)
   3654 else:
   3655     # set column
-> 3656     self._set_item(key, value)

File /usr/local/Cellar/ipython/8.0.1/libexec/lib/python3.10/site-packages/pandas/core/frame.py:3833, in DataFrame._set_item(self, key, value)
   3823 def _set_item(self, key, value) -> None:
   3824     """
   3825     Add series to DataFrame in specified column.
   3826 
   (...)
   3831     ensure homogeneity.
   3832     """
-> 3833     value = self._sanitize_column(value)
   3835     if (
   3836         key in self.columns
   3837         and value.ndim == 1
   3838         and not is_extension_array_dtype(value)
   3839     ):
   3840         # broadcast across multiple columns if necessary
   3841         if not self.columns.is_unique or isinstance(self.columns, MultiIndex):

File /usr/local/Cellar/ipython/8.0.1/libexec/lib/python3.10/site-packages/pandas/core/frame.py:4534, in DataFrame._sanitize_column(self, value)
   4532 # We should never get here with DataFrame value
   4533 if isinstance(value, Series):
-> 4534     return _reindex_for_setitem(value, self.index)
   4536 if is_list_like(value):
   4537     com.require_length_match(value, self.index)

File /usr/local/Cellar/ipython/8.0.1/libexec/lib/python3.10/site-packages/pandas/core/frame.py:10985, in _reindex_for_setitem(value, index)
  10981     if not value.index.is_unique:
  10982         # duplicate axis
  10983         raise err
> 10985     raise TypeError(
  10986         "incompatible index of inserted column with frame index"
  10987     ) from err
  10988 return reindexed_value

TypeError: incompatible index of inserted column with frame index

```