anchor.diff:  A `subject` contains the following subfields:
   
   + `entities`: A list of objects, each one composed of the following subfields (`id`/`idPattern` or `type` must be present):
  -    + `id` or `idPattern`: Id or pattern of the affected entities (optional). Both cannot be used at the same time.
  +    + `id` or `idPattern`: Id or pattern of the affected entities. Both cannot be used at the same time, but at least one of them must be set.
       + `type`: Type of the affected entities (optional).
   + `condition`: Condition that will trigger the notification. It can have two optional properties:
       + `attributes`: array of attribute names
  
positive.code: A `subject` contains the following subfields:
  
  + `entities`: A list of objects, each one composed of the following subfields (`id`/`idPattern` or type must be present):
      + `id` or `idPattern`: Id or pattern of the affected entities (optional). Both cannot be used at the same time.
      + `type`: Type of the affected entities (optional).
  + `attributes`: List of attributes to be provided (if not specified it would mean all).
  
  
negative.code:             "subject": {
                  "entities": [
                      {
                          "idPattern": ".*",
                          "type": "Room"
                      }
                  ],
                  "condition": {
                      "attributes": [ "temperature" ],
                      "expression": {
                         "q": "temperature>40"
                      }
  