Returns the fileDesc object or None if there is no such element
        @return: the fileDesc object
        @rtype: L{CfileDesc}

def get_fileDesc(self):
        '''
        Returns the fileDesc object or None if there is no such element
        @return: the fileDesc object
        @rtype: L{CfileDesc}
        '''
        node = self.node.find('fileDesc')
        if node is not None:
            return CfileDesc(node=node)
        else:
            return None