Clarify list/set/dict/tuple comprehensions and enforce via flake8 (#6957)

Ensure good comprehension hygiene using flake8-comprehensions.

1 files changed, 3 insertions, 3 deletions

diff --git a/synapse/storage/prepare_database.py b/synapse/storage/prepare_database.py
index c285ef52a0..fc69c32a0a 100644
--- a/synapse/storage/prepare_database.py
+++ b/synapse/storage/prepare_database.py
@@ -345,9 +345,9 @@ def _upgrade_existing_database(
                     "Could not open delta dir for version %d: %s" % (v, directory)
                 )
 
-        duplicates = set(
+        duplicates = {
             file_name for file_name, count in file_name_counter.items() if count > 1
-        )
+        }
         if duplicates:
             # We don't support using the same file name in the same delta version.
             raise PrepareDatabaseException(
@@ -454,7 +454,7 @@ def _apply_module_schema_files(cur, database_engine, modname, names_and_streams)
         ),
         (modname,),
     )
-    applied_deltas = set(d for d, in cur)
+    applied_deltas = {d for d, in cur}
     for (name, stream) in names_and_streams:
         if name in applied_deltas:
             continue