Unable to remove the label from the Kubernetes cluster node pool.

Unable to remove the label for the Kubernetes cluster node pool.

For adding a persistent node label to the Kubernetes worker nodes, we need to label the node pool using doctl. Once the label has been added how to remove it?

The documentation says the omitted labels will be removed. But how to remove the last label?

For example, if we use the below command to add 3 labels to the node pool.

`doctl kubernetes cluster node-pool update --label key1=value1,key2=value2,key3=value3`

We can remove the label key2=value2,key3=value3 using the below command
`doctl kubernetes cluster node-pool update --label key1=value1`

But how to remove key1=value1 label? The below command doesn't work.
`doctl kubernetes cluster node-pool update --label`

The label can be removed using the API call but using doctl it seems there isn't a way.
```
curl -X PUT \
-H "Content-Type: application/json" \
-H "Authorization: Bearer " \
-d '{"name": " ","count": 3, "tags":["null"], "labels": {}}' \
"https://api.digitalocean.com/v2/kubernetes/clusters//node_pools/"
```