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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 dtdQAttrDesc(self, elem, name, prefix):
 """Search the DTD for the description of this qualified attribute on this element. """

        ret = libxml2mod.xmlGetDtdQAttrDesc(self._o, elem, name, prefix)
        if ret is None:raise treeError('xmlGetDtdQAttrDesc() failed')
        __tmp = xmlAttribute(_obj=ret)
        return __tmp