@spec account(
  String.t() | atom(),
  keyword()
) :: {:ok, map()} | {:error, term()}

@spec provider(String.t() | atom()) :: module() | nil

@spec providers() :: %{required(String.t()) => module()}

@spec usage(
  String.t() | atom(),
  keyword()
) :: {:ok, map()} | {:error, term()}