LookupNumber valid_number is not documented

[pauldraper]

The LookupNumber response has an valid_number property that is not documented.

Example:

{
  "data": {
    "country_code": "BR",
    "national_format": "5555-5555",
    "phone_number": "+5555555555",
    "fraud": null,
    "carrier": null,
    "caller_name": null,
    "nnid_override": null,
    "portability": null,
    "valid_number": false,
    "record_type": "number_lookup"
  }
}