code: def newNs(self, href, prefix):
          
          ret = libxml2mod.xmlNewNs(self._o, href, prefix)
          if ret is None:raise treeError('xmlNewNs() failed')
          __tmp = xmlNs(_obj=ret)
          return __tmp
docs: Creation of a new Namespace. This function will refuse to
            create a namespace with a similar prefix than an existing
            one present on this node. We use href==None in the case of
             an element creation where the namespace was not defined.