@type t() :: %Docspring.Model.CombinedSubmission{
  actions: [CombinedSubmissionAction],
  download_url: String.t(),
  expired: boolean(),
  expires_at: String.t(),
  id: String.t(),
  metadata: Object,
  password: String.t(),
  pdf_hash: String.t(),
  source_pdfs: [Object],
  state: String.t(),
  submission_ids: [String.t()]
}