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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def removeNsDef(self, href):
 """ Remove a namespace definition from a node. If href is None, remove all of the ns definitions on that node. The removed namespaces are returned as a linked list. Note: If any child nodes referred to the removed namespaces, they will be left with dangling links. You should call renconciliateNs() to fix those pointers. Note: This method does not free memory taken by the ns definitions. You will need to free it manually with the freeNsList() method on the returns xmlNs object. """


        ret = libxml2mod.xmlNodeRemoveNsDef(self._o, href)
        if ret is None:return None
        __tmp = xmlNs(_obj=ret)
        return __tmp