Getting Key Error trying to use the given Solution to Relations between Tags (469-8)

Screen Link:
Question: https://app.dataquest.io/m/469/guided-project%3A-popular-data-science-questions/8/relations-between-tags
Solution: https://github.com/dataquestio/solutions/blob/master/Mission469Solutions.ipynb

My Code:

all_tags = list(tag_usage.index)

tag_associations = pd.DataFrame(index=all_tags, columns=all_tags)
tag_associations.fillna(0, inplace=True)

for tags in questions['Tags']:
    tag_associations.loc[tags,tags] += 1
    
print(tag_associations)

What I expected to happen:
Print the same data frame found in the solution.

What actually happened:
I keep seeing an error: ‘Passing list-likes to .loc or with any missing labels is no longer supported, see https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#deprecate-loc-reindex-listlike

KeyError                                  Traceback (most recent call last)
<ipython-input-24-463258644b32> in <module>
      5 
      6 for tags in questions['Tags']:
----> 7     tag_associations.loc[tags,tags] += 1
      8 
      9 print(tag_associations)

~/opt/anaconda3/lib/python3.8/site-packages/pandas/core/indexing.py in __getitem__(self, key)
   1760                 except (KeyError, IndexError, AttributeError):
   1761                     pass
-> 1762             return self._getitem_tuple(key)
   1763         else:
   1764             # we by definition only have the 0th axis

~/opt/anaconda3/lib/python3.8/site-packages/pandas/core/indexing.py in _getitem_tuple(self, tup)
   1279         # ugly hack for GH #836
   1280         if self._multi_take_opportunity(tup):
-> 1281             return self._multi_take(tup)
   1282 
   1283         # no shortcut needed

~/opt/anaconda3/lib/python3.8/site-packages/pandas/core/indexing.py in _multi_take(self, tup)
   1336         # GH 836
   1337         o = self.obj
-> 1338         d = {
   1339             axis: self._get_listlike_indexer(key, axis)
   1340             for (key, axis) in zip(tup, o._AXIS_ORDERS)

~/opt/anaconda3/lib/python3.8/site-packages/pandas/core/indexing.py in <dictcomp>(.0)
   1337         o = self.obj
   1338         d = {
-> 1339             axis: self._get_listlike_indexer(key, axis)
   1340             for (key, axis) in zip(tup, o._AXIS_ORDERS)
   1341         }

~/opt/anaconda3/lib/python3.8/site-packages/pandas/core/indexing.py in _get_listlike_indexer(self, key, axis, raise_missing)
   1550             keyarr, indexer, new_indexer = ax._reindex_non_unique(keyarr)
   1551 
-> 1552         self._validate_read_indexer(
   1553             keyarr, indexer, o._get_axis_number(axis), raise_missing=raise_missing
   1554         )

~/opt/anaconda3/lib/python3.8/site-packages/pandas/core/indexing.py in _validate_read_indexer(self, key, indexer, axis, raise_missing)
   1652             # just raising
   1653             if not (ax.is_categorical() or ax.is_interval()):
-> 1654                 raise KeyError(
   1655                     "Passing list-likes to .loc or [] with any missing labels "
   1656                     "is no longer supported, see "

KeyError: 'Passing list-likes to .loc or [] with any missing labels is no longer supported, see https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#deprecate-loc-reindex-listlike'

I did use slightly different variables from the solution, but that shouldn’t have changed anything. I tried copying the solution (with the same variable), and I saw the same error. I went back to make sure i had all of the same data for questions[‘Tags’], and that my tag_usage matches the solution’s tag_count, and they should match. It may be that support dropped in Python 3.8, but I want to make sure I’m not doing something wrong (and learn from it if so). Thanks!