--- a/Utilities/ClassBrowsers/idlclbr.py	Wed Mar 22 18:45:15 2017 +0100
+++ b/Utilities/ClassBrowsers/idlclbr.py	Wed Mar 22 18:50:20 2017 +0100
@@ -181,7 +181,7 @@
         VisibilityMixin.__init__(self)
 
 
-def readmodule_ex(module, path=[]):
+def readmodule_ex(module, path=None):
     """
     Read a CORBA IDL file and return a dictionary of classes, functions and
     modules.
@@ -201,7 +201,7 @@
 
     # search the path for the file
     f = None
-    fullpath = list(path)
+    fullpath = [] if path is None else path[:]
     f, file, (suff, mode, type) = ClassBrowsers.find_module(module, fullpath)
     if f:
         f.close()