Moar.Random.string/2 guard is wrong

[eahanson]

  def string(character_count \\ 32, encoding \\ :base64) when is_number(32) and encoding in [:base32, :base64] do
    character_count
    |> :crypto.strong_rand_bytes()
    |> encode(encoding)
    |> binary_part(0, character_count)
  end

when is_number(32) should be when is_number(character_count)