diff --git a/synapse/rest/media/v1/_base.py b/synapse/rest/media/v1/_base.py
index 65bbf00073..ba28dd089d 100644
--- a/synapse/rest/media/v1/_base.py
+++ b/synapse/rest/media/v1/_base.py
@@ -135,27 +135,25 @@ def add_file_headers(request, media_type, file_size, upload_name):
# separators as defined in RFC2616. SP and HT are handled separately.
# see _can_encode_filename_as_token.
-_FILENAME_SEPARATOR_CHARS = set(
- (
- "(",
- ")",
- "<",
- ">",
- "@",
- ",",
- ";",
- ":",
- "\\",
- '"',
- "/",
- "[",
- "]",
- "?",
- "=",
- "{",
- "}",
- )
-)
+_FILENAME_SEPARATOR_CHARS = {
+ "(",
+ ")",
+ "<",
+ ">",
+ "@",
+ ",",
+ ";",
+ ":",
+ "\\",
+ '"',
+ "/",
+ "[",
+ "]",
+ "?",
+ "=",
+ "{",
+ "}",
+}
def _can_encode_filename_as_token(x):
|