Use RelaxNG schema to validate the document as it is
          processed. Activation is only possible before the first
          Read(). If @rng is None, then RelaxNG schema validation is
           deactivated.

def RelaxNGValidate(self, rng):
        """Use RelaxNG schema to validate the document as it is
          processed. Activation is only possible before the first
          Read(). If @rng is None, then RelaxNG schema validation is
           deactivated. """
        ret = libxml2mod.xmlTextReaderRelaxNGValidate(self._o, rng)
        return ret