       Dict.get d, :b, 3  #=> 3
 
   """
+  @spec get(t, key), do: value | nil
+  @spec get(t, key, value), do: value
   def get(dict, key, default // nil) do
     elem(dict, 0).get(dict, key, default)
   end

  @doc """
  Returns an empty dict of the same type as `dict`.
  """
  def empty(dict) do
    elem(dict, 0).empty(dict)
  end

      Dict.values d  #=> [1,2]

  """
  @spec values(t), do: [value]
  def values(dict) do
    elem(dict, 0).values(dict)
  end
