use update and add what's new

Author: malmans2

cf_xarray/accessor.py

@@ -1614,7 +1614,7 @@ def add_bounds(self, keys: Union[str, Iterable[str]]):
 
         dimensions = set()
         for key in keys:
-            dimensions |= set(
+            dimensions.update(
                 apply_mapper(_get_dims, self._obj, key, error=False, default=[key])
             )
 

doc/whats-new.rst

@@ -6,6 +6,7 @@ What's New
 v0.5.2 (unreleased)
 ===================
 
+- Replace the ``dims`` argument of :py:meth:`Dataset.cf.add_bounds` with ``keys``, allowing to use CF keys. By `Mattia Almansi`_.
 - Added :py:attr:`DataArray.cf.formula_terms` and :py:attr:`Dataset.cf.formula_terms`.
   By `Deepak Cherian`_.
 - Added :py:attr:`Dataset.cf.bounds` to return a dictionary mapping valid keys to the variable names of their bounds. By `Mattia Almansi`_.