Programatically accessing the definition of typespec

How might I access the definition of a typespec within my code? I wish to use it within a macro in order to perform some code generation.

Something like this would be ideal.

Given this module and typespec:

defmodule MyMod do
  @type t :: :ok | :error
end

I could call a function such as Code.get_type(MyMod, :t) and it would return the AST of the definition expression:

{:::, [], [{:my_type, [], Elixir}, {:|, [], [:ok, :error]}]}

Or alternatively just the AST of the type:

{:|, [], [:ok, :error]}