anchor.diff:  
   + Response 204
   
  +<!--
  +
   ## Attribute by Entity Type and ID [/v2/entities/type/{entityType}/id/{entityId}/attrs/{attrName}]
   
   ### Get attribute data [GET /v2/entities/type/{entityType}/id/{entityId}/attrs/{attrName}]
  
positive.code: 
  + Response 200
  
  ## Attribute Value by Entity type and ID [/v2/entities/type/{entityType}/id/{entityId}/attrs/{attrName}/value{?options}]
  
  ### Get attribute data [GET /v2/entities/type/{entityType}/id/{entityId}/attrs/{attrName}/value{?options}]
  
negative.code: + Response 200 (application/json)
  
          {
            "Car": {
              "attrs": {
                "speed": {
                  "type": null
                },
                "fuel": {
                  "type": "gasoline"
                },
                "fuel": {
                  "type": "diesel"
                },
                "temperature": {
                  "type": "urn:phenomenum:temperature"
                }
              },
              "count": 12
            },
            "Room": {
              "attrs": {
                "pressure": {
                  "type": null
                },
                "hummidity": {
                  "type": "percentage"
                },
                "temperature": {
                  "type": "urn:phenomenum:temperature"
                }
              },
              "count": 7
            }
          }
  
  ## Entity type [/v2/type/{entityType}]
  
  ### Retrieve entity type [GET /v2/type/{entityType}]
  
  The operation returns a JSON object with information about the type: `attrs` (the union set of attribute names along all
  the entities of such type) and `count` (the number of entities belonging to that type).
  
  Response code:
  
  