diff --git a/sweeper/sweeper.py b/sweeper/sweeper.py
index 79b279d..fc5aabe 100644
--- a/sweeper/sweeper.py
+++ b/sweeper/sweeper.py
@@ -109,11 +109,7 @@ def _filehash(filepath, hashalg, block_size):
 
 
 def _uniq_list(list_):
-    result = []
-    for foo in list_:
-        if foo not in result:
-            result.append(foo)
-    return result
+    return set(list_)
 
 
 def _gather_file_list(dirs):
@@ -128,8 +124,8 @@ def _gather_file_list(dirs):
         for dirpath, dirnames, filenames in os.walk(dir_):
             count += len(filenames)
             # replace fpath with realpath value (eliminate symbolic links)
-            files += [os.path.realpath(os.path.join(dirpath, fname))
-                      for fname in filenames]
+            files.extend([os.path.realpath(os.path.join(dirpath, fname))
+                      for fname in filenames])
     return (count, files)