   @doc """
   Registers a function to be invoked after the IEx process is spawned.
   """
+  @spec after_spawn(fun()) :: :ok
   def after_spawn(fun) when is_function(fun) do
     IEx.Config.after_spawn(fun)
   end

  @doc """
  Returns registered `after_spawn` callbacks.
  """
  def after_spawn do
    IEx.Config.after_spawn()
  end

  @doc """
  Returns `true` if IEx was started.
  """
  def started? do
    IEx.Config.started?()
  end

  end

  @doc """
  Returns the IEx width for printing.

  Used by helpers and it has a default maximum cap of 80 chars.
  """
  @spec width() :: pos_integer()
  def width do
    IEx.Config.width()
  end

  @doc """
  Returns the options used for inspecting.
  """
  @spec inspect_opts() :: keyword()
  def inspect_opts do
    IEx.Config.inspect_opts()
  end
