TypeError                                 Traceback (most recent call last)
<ipython-input-10-d6ae260d158c> in <module>
    2 from numpy import array
    3 df = pd.DataFrame({"status": ["a", "b", "c"]},  dtype="category")
----> 4 df.iloc[array([0, 1]), array([0])] = array([['a'], ['a']])

~/pandas/pandas/core/indexing.py in __setitem__(self, key, value)
  708
  709         iloc = self if self.name == "iloc" else self.obj.iloc
--> 710         iloc._setitem_with_indexer(indexer, value, self.name)
  711
  712     def _validate_key(self, key, axis: int):

~/pandas/pandas/core/indexing.py in _setitem_with_indexer(self, indexer, value, name)
 1671             self._setitem_with_indexer_split_path(indexer, value, name)
 1672         else:
-> 1673             self._setitem_single_block(indexer, value, name)
 1674
 1675     def _setitem_with_indexer_split_path(self, indexer, value, name: str):

~/pandas/pandas/core/indexing.py in _setitem_single_block(self, indexer, value, name)
 1919
 1920         # actually do the set
-> 1921         self.obj._mgr = self.obj._mgr.setitem(indexer=indexer, value=value)
 1922         self.obj._maybe_update_cacher(clear=True, inplace=True)
 1923

~/pandas/pandas/core/internals/managers.py in setitem(self, indexer, value)
  335         For SingleBlockManager, this backs s[indexer] = value
  336         """
--> 337         return self.apply("setitem", indexer=indexer, value=value)
  338
  339     def putmask(self, mask, new, align: bool = True):

~/pandas/pandas/core/internals/managers.py in apply(self, f, align_keys, ignore_failures, **kwargs)
  302                     applied = b.apply(f, **kwargs)
  303                 else:
--> 304                     applied = getattr(b, f)(**kwargs)
  305             except (TypeError, NotImplementedError):
  306                 if not ignore_failures:

~/pandas/pandas/core/internals/blocks.py in setitem(self, indexer, value)
 1513
 1514         check_setitem_lengths(indexer, value, self.values)
-> 1515         self.values[indexer] = value
 1516         return self
 1517

~/pandas/pandas/core/arrays/_mixins.py in __setitem__(self, key, value)
  249     def __setitem__(self, key, value):
  250         key = check_array_indexer(self, key)
--> 251         value = self._validate_setitem_value(value)
  252         self._ndarray[key] = value
  253

~/pandas/pandas/core/arrays/categorical.py in _validate_setitem_value(self, value)
 1445         if not is_hashable(value):
 1446             # wrap scalars and hashable-listlikes in list
-> 1447             return self._validate_listlike(value)
 1448         else:
 1449             return self._validate_scalar(value)

~/pandas/pandas/core/arrays/categorical.py in _validate_listlike(self, value)
 2080         # something to np.nan
 2081         if len(to_add) and not isna(to_add).all():
-> 2082             raise TypeError(
 2083                 "Cannot setitem on a Categorical with a new "
 2084                 "category, set the categories first"

TypeError: Cannot setitem on a Categorical with a new category, set the categories first