   end
 
   @doc """
-  The identity function lifted into an arrow of the correct type
+  The identity function lifted into an arrow of the correct type.
 
   ## Examples
 

  end

  @doc """
  Target the second element of a tuple

  ## Examples


  def product(arrow_f, arrow_g), do: first(arrow_f) <~> second(arrow_g)

  @doc """
  Alias for `product/2`, meant to invoke a spacial metaphor.

  ## Examples

