A single agify result: the prediction fields plus the response :quota.
:age is an integer or nil. :country_id is set only when the request sent
a country_id.
Summary
Types
@type t() :: %Demografix.Agify{ age: integer() | nil, count: integer(), country_id: String.t() | nil, name: String.t(), quota: Demografix.Quota.t() }