diff --git a/src/sourmash/commands.py b/src/sourmash/commands.py
index a96c34dd5..0b25f34d5 100644
--- a/src/sourmash/commands.py
+++ b/src/sourmash/commands.py
@@ -1234,7 +1234,7 @@ def multigather(args):
                 output_base = query.md5sum()
             elif args.output_add_query_md5sum:
                 # Uniquify the output file if all signatures were made from the same file (e.g. with --singleton)
-                assert query_filename and query_filename != '-' # first branch
+                assert query_filename and query_filename != "-"  # first branch
                 output_base = os.path.basename(query_filename) + "." + query.md5sum()
             else:
                 output_base = os.path.basename(query_filename)
diff --git a/tests/test_sourmash.py b/tests/test_sourmash.py
index 26ae54f69..fc083a21e 100644
--- a/tests/test_sourmash.py
+++ b/tests/test_sourmash.py
@@ -5418,9 +5418,9 @@ def test_multigather_metagenome_output_unique(runtmp):
     # change 'filename' on 'combined.sig' to something else
     orig_query_sig = utils.get_test_data("gather/combined.sig")
     sketch = sourmash.load_one_signature(orig_query_sig)
-    ss = signature.SourmashSignature(sketch.minhash, filename='named_query')
+    ss = signature.SourmashSignature(sketch.minhash, filename="named_query")
 
-    query_sig = runtmp.output('the_query.sig')
+    query_sig = runtmp.output("the_query.sig")
     with open(query_sig, "w") as f:
         signature.save_signatures([ss], f)