diff --git a/tldp/utils.py b/tldp/utils.py
index 40127ba..f370c52 100644
--- a/tldp/utils.py
+++ b/tldp/utils.py
@@ -24,6 +24,7 @@ def getLogger(**opts):
 
 logger = getLogger()
 
+
 def firstfoundfile(locations):
     '''return the first existing file from a list of filenames (or None)'''
     for option in locations:
@@ -32,6 +33,12 @@ def firstfoundfile(locations):
     return None
 
 
+def isdirectory(d):
+    if os.path.exists(d):
+        return d
+    return None
+
+
 def stem_and_ext(name):
     '''return (stem, ext) for any relative or absolute filename'''
     return os.path.splitext(os.path.basename(os.path.normpath(name)))