Creation of a new node containing a CDATA block.

def newCDataBlock(self, content, len):
        """Creation of a new node containing a CDATA block. """
        ret = libxml2mod.xmlNewCDataBlock(self._o, content, len)
        if ret is None:raise treeError('xmlNewCDataBlock() failed')
        __tmp = xmlNode(_obj=ret)
        return __tmp