t() :: %Fiet.Atom.Feed{
  authors: [Fiet.Atom.Person.t()],
  categories: [Fiet.Atom.Category.t()],
  contributors: [Fiet.Atom.Person.t()],
  entries: [Fiet.Atom.Entry.t()],
  generator: Fiet.Atom.Generator.t() | nil,
  icon: binary() | nil,
  id: binary() | nil,
  links: [Fiet.Atom.Link.t()],
  logo: binary() | nil,
  rights: {:text | :html, title :: binary()} | nil,
  subtitle: {:text | :html, title :: binary()} | nil,
  title: {:text | :html, title :: binary()} | nil,
  updated: binary() | nil
}