 
   @spec start() :: any
   def start do
-    []
+    %Bowling{}
   end
 
   @doc """

defmodule Bowling do
  @doc """
  Creates a new game of bowling that can be used to store the results of
  the game

  """

  @spec roll(any, integer) :: any | String.t
  def roll(%Bowling{frames: frames}, roll), do: %Bowling{frames: frames ++ [roll]}
  @doc """
  Returns the score of a given game of bowling if the game is complete.
  If the game isn't complete, it returns a helpful message.
  """
  @spec score(any) :: integer | String.t
  def score(%Bowling{frames: frames}) do
    games = frames
    |> Enum.flat_map(fn
      10 -> [10, nil]
      a -> [a]
