diff --git a/onionrblocks/universalrules.py b/onionrblocks/universalrules.py
index 9c02c35..32e4443 100644
--- a/onionrblocks/universalrules.py
+++ b/onionrblocks/universalrules.py
@@ -30,7 +30,8 @@ class BlockTooLarge(BlockRulesException):
 def checksum_exists_in_list(checksum: bytes, arr: 'Iterable'):
     if checksum in arr:
         raise BlockExistsError(
-            binascii.hexlify(checksum).decode("utf-8") + " Already exists in given set")
+            binascii.hexlify(
+                checksum).decode("utf-8") + " Already exists in given set")
 
 
 def check_block_sanity(raw_bytes):