Get the value for a key. If there is no value for the key then empty
        string is returned.

def get_parallel_value_for_key(self, key):
        """
        Get the value for a key. If there is no value for the key then empty
        string is returned.
        """
        if self._remotelib:
            return self._remotelib.run_keyword('get_parallel_value_for_key',
                                               [key], {})
        return _PabotLib.get_parallel_value_for_key(self, key)