[XML-SIG] problem whith the error " ImportError: cannot import name boolean"

[Nicolas]

I' ve just installed python and here the probleme: it gives me the 
following error:
                  >>> from Ft.Xml.Xslt import Processor
                      Traceback (most recent call last):
                       File "<stdin>", line 1, in ?
                       File "Ft/Xml/Xslt/__init__.py", line 41, in ?
                         from Ft.Xml import XPath
                       File "Ft/Xml/XPath/__init__.py", line 25, in ?
                          from Ft.Lib import boolean
                        ImportError: cannot import name boolean
 
what must I make to solve this problem?