code: def validCtxtNormalizeAttributeValue(self, ctxt, elem, name, value):
          
          if ctxt is None: ctxt__o = None
          else: ctxt__o = ctxt._o
          if elem is None: elem__o = None
          else: elem__o = elem._o
          ret = libxml2mod.xmlValidCtxtNormalizeAttributeValue(ctxt__o, self._o, elem__o, name, value)
          return ret
docs: Does the validation related extra step of the normalization
            of attribute values:  If the declared value is not CDATA,
            then the XML processor must further process the normalized
            attribute value by discarding any leading and trailing
            space (#x20) characters, and by replacing sequences of
            space (#x20) characters by single space (#x20) character.
            Also  check VC: Standalone Document Declaration in P32, and
             update ctxt->valid accordingly