def enable_checkpoint(self, step: str) -> None:
        """Enable checkpointing after the completion of the specified step."""
        if step not in self.workflow._get_steps():
            msg = f"This workflow does not contain a step with name {step}"
            raise WorkflowStepDoesNotExistError(msg)

        self.enabled_checkpoints.add(step)
Enable checkpointing after the completion of the specified step.
llama-index-core/llama_index/core/workflow/checkpointer.py