Function build_checkpoint_with_previous 

pub fn build_checkpoint_with_previous(
    checkpoint_seq: u64,
    batch_start_seq: u64,
    batch_end_seq: u64,
    receipt_canonical_bytes_batch: &[Vec<u8>],
    keypair: &Keypair,
    previous_checkpoint: Option<&KernelCheckpoint>,
) -> Result<KernelCheckpoint, CheckpointError>

Build a signed kernel checkpoint that explicitly links to the previous checkpoint when provided.