>>> $CLI bundle validate -o json -t dev
{
  "clusters": {
    "my_cluster": {
      "custom_tags": {},
      "spark_version": "25"
    }
  }
}

>>> $CLI bundle validate -t dev
Warning: expected map, found string
  at resources.clusters.my_cluster
  in databricks.yml:6:17

Name: merge-string-map
Target: dev
Workspace:
  User: tester@databricks.com
  Path: /Workspace/Users/tester@databricks.com/.bundle/merge-string-map/dev

Found 1 warning