Validate a branch of a tree, starting with the given @elem.

def schemaValidateOneElement(self, ctxt):
        """Validate a branch of a tree, starting with the given @elem. """
        if ctxt is None: ctxt__o = None
        else: ctxt__o = ctxt._o
        ret = libxml2mod.xmlSchemaValidateOneElement(ctxt__o, self._o)
        return ret