   @doc """
   Returns the Mix target.
   """
+  @spec target() :: atom()
   def target do
     # target is not available on bootstrapping, so set a :host default
     Mix.State.get(:target, :host)

  end

  @doc """
  Returns the Mix environment.

  This function should not be used at runtime in application code (as opposed
  to infrastructure and build code like Mix tasks). Mix is a build tool and may

  @doc """
  Sets Mix debug mode.
  """
  @spec debug(boolean()) :: :ok
  def debug(debug) when is_boolean(debug) do
    Mix.State.put(:debug, debug)
  end
