diff --git a/roles/distgit/files/make-new-lookaside-links b/roles/distgit/files/make-new-lookaside-links
index 09fdf9533d..33cbba5aad 100755
--- a/roles/distgit/files/make-new-lookaside-links
+++ b/roles/distgit/files/make-new-lookaside-links
@@ -68,7 +68,7 @@ def get_file_hash(full_path, hashtype):
 
 
 def verify_source(dir, expected_name, expected_hash, hashtype):
-    sources = listdir(dir)
+    sources = list(listdir(dir))
 
     if len(sources) == 0:
         raise Exception("No source file in %s" % dir)