@type t() :: %Gumroad.Product{
  currency: String.t(),
  custom_fields: list(),
  custom_permalink: String.t() | nil,
  custom_receipt: String.t() | nil,
  custom_summary: String.t(),
  customizable_price: String.t() | nil,
  deleted: boolean(),
  description: String.t(),
  file_info: map(),
  formatted_price: String.t(),
  id: String.t(),
  is_tiered_membership: boolean(),
  max_purchase_count: integer() | nil,
  name: String.t(),
  preview_url: String.t() | nil,
  price: number(),
  published: boolean(),
  recurrences: [String.t()],
  require_shipping: boolean(),
  sales_count: number(),
  sales_usd_cents: number(),
  short_url: String.t(),
  shown_on_profile: boolean(),
  subscription_duration: String.t() | nil,
  tags: [String.t()],
  thumbnail_url: String.t(),
  url: String.t(),
  variants: [variant()]
}

@type variant() :: %{title: String.t(), options: [variant_option()]}

@type variant_option() :: %{
  name: String.t(),
  price_difference: number(),
  is_pay_what_you_want: boolean(),
  recurrence_prices: %{
    optional(any()) => %{price_cents: number(), suggested_price_cents: number()}
  }
}