diff --git a/installinstallmacos.py b/installinstallmacos.py
index 9876e5d..dfbf353 100755
--- a/installinstallmacos.py
+++ b/installinstallmacos.py
@@ -47,21 +47,21 @@
 
 
 DEFAULT_SUCATALOGS = {
-    "17": "https://swscan.apple.com/content/catalogs/others/"
-    "index-10.13-10.12-10.11-10.10-10.9"
-    "-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog",
-    "18": "https://swscan.apple.com/content/catalogs/others/"
-    "index-10.14-10.13-10.12-10.11-10.10-10.9"
-    "-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog",
-    "19": "https://swscan.apple.com/content/catalogs/others/"
-    "index-10.15-10.14-10.13-10.12-10.11-10.10-10.9"
-    "-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog",
-    "20": "https://swscan.apple.com/content/catalogs/others/"
-    "index-10.16-10.15-10.14-10.13-10.12-10.11-10.10-10.9"
-    "-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog",
-    "21": "https://swscan.apple.com/content/catalogs/others/"
-    "index-12-10.16-10.15-10.14-10.13-10.12-10.11-10.10-10.9"
-    "-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog",
+    '17': 'https://swscan.apple.com/content/catalogs/others/'
+          'index-10.13-10.12-10.11-10.10-10.9'
+          '-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog',
+    '18': 'https://swscan.apple.com/content/catalogs/others/'
+          'index-10.14-10.13-10.12-10.11-10.10-10.9'
+          '-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog',
+    '19': 'https://swscan.apple.com/content/catalogs/others/'
+          'index-10.15-10.14-10.13-10.12-10.11-10.10-10.9'
+          '-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog',
+    '20': 'https://swscan.apple.com/content/catalogs/others/'
+          'index-10.16-10.15-10.14-10.13-10.12-10.11-10.10-10.9'
+          '-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog',
+    '21': 'https://swscan.apple.com/content/catalogs/others/'
+          'index-12-10.16-10.15-10.14-10.13-10.12-10.11-10.10-10.9'
+          '-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog',
 }
 
 SEED_CATALOGS_PLIST = (