Identifiers
When an object is documented as having a unique identifier, the identifier is expected to be a uniquelyidentifying string. When requesting the creation of an object, a client may assign a unique identifier string to the object. The chosen identifier is subject to approval by the API backend, however; if the server is dissatisfied with the chosen identifier, the creation request will fail with an HTTP status of 422 Unprocessable Entity and will include an error message describing the reason.
If a client does not assign a unique identifier to the object being created, the server will assign one.