@type t() :: %Docspring.Model.ValidateSubmissionRequest{
  css: String.t() | nil,
  data: %{optional(String.t()) => any()} | nil,
  editable: boolean() | nil,
  expires_in: integer() | nil,
  field_overrides:
    %{optional(String.t()) => Docspring.Model.FieldOverride.t()} | nil,
  html: String.t() | nil,
  metadata: %{optional(String.t()) => any()} | nil,
  output_formats: [Docspring.Model.OutputFormat.t()] | nil,
  password: String.t() | nil,
  signature_requests: [Docspring.Model.SignatureRequestInput.t()] | nil,
  test: boolean() | nil
}