     * `:description` - A description or product name
     * `:serial_number` - The device's serial number if it has one
   """
+  @spec enumerate() :: map
   def enumerate() do
     Nerves.UART.Enumerator.enumerate
   end

    * `:eagain`  - the port is already open
    * `:eacces`  - permission was denied when opening the port
  """
  def open(pid, name, opts \\ []) do
    GenServer.call pid, {:open, name, opts}
  end

  Change the serial port configuration after `open/3` has been called. See
  `open/3` for the valid options.
  """
  @spec configure(pid, [uart_option]) :: :ok | {:error, term}
  def configure(pid, opts) do
    GenServer.call pid, {:configure, opts}
  end
