diff --git a/IPython/core/completer.py b/IPython/core/completer.py
index a969045..4928b92 100644
--- a/IPython/core/completer.py
+++ b/IPython/core/completer.py
@@ -121,7 +121,7 @@ def protect_filename(s):
         if sys.platform == "win32":
             return '"' + s + '"'
         else:
-            return "".join("\\" + c if c in PROTECTABLES else c for c in s)
+            return "".join(("\\" + c if c in PROTECTABLES else c) for c in s)
     else:
         return s
 
diff --git a/IPython/utils/path.py b/IPython/utils/path.py
index 1a6cd8e..1d2c9e8 100644
--- a/IPython/utils/path.py
+++ b/IPython/utils/path.py
@@ -73,6 +73,9 @@ def get_long_path_name(path):
 
 def unquote_filename(name, win32=(sys.platform=='win32')):
     """ On Windows, remove leading and trailing quotes from filenames.
+
+    This function has been deprecated and should not be used any more:
+    unquoting is now taken care of by :func:`IPython.utils.process.arg_split`.
     """
     warn("'unquote_filename' is deprecated", DeprecationWarning)
     if win32:
@@ -83,7 +86,7 @@ def unquote_filename(name, win32=(sys.platform=='win32')):
 
 def compress_user(path):
     """Reverse of :func:`os.path.expanduser`
-    """    
+    """
     path = py3compat.unicode_to_str(path, sys.getfilesystemencoding())
     home = os.path.expanduser('~')
     if path.startswith(home):