def _def_check(self):
        """
        Checks that the definition provided contains only valid arguments for a
        text index.
        """
        if self._def != dict():
            for key, val in iteritems_(self._def):
                if key not in list(TEXT_INDEX_ARGS.keys()):
                    raise CloudantArgumentError(127, key)
                if not isinstance(val, TEXT_INDEX_ARGS[key]):
                    raise CloudantArgumentError(128, key, TEXT_INDEX_ARGS[key])
Checks that the definition provided contains only valid arguments for a
        text index.