anchor.diff:  
       datastore_pattern: '\Aprod-ds\z'
       persistent_datastore_pattern: '\Aprod-ds\z'
  -    allow_mixed_datastores: true
   
       clusters: [BOSH_CL]
   ```
  
positive.code: 
      datastore_pattern: '\Aprod-ds\z'
      persistent_datastore_pattern: '\Aprod-ds\z'
      allow_mixed_datastores: true
  
      clusters:
      - BOSH_CL: {resource_pool: BOSH_RP}
  
negative.code: Field object_set is not optional
  ```
  
  This error may occur when global CPI configuration references:
  
  - cluster (via `clusters` key) that cannot be found in the datacenter
  - stemcell that cannot be found in the templates folder
  