   @doc "Returns the list of modules used in a given module source code."
   def modules({:defmodule, _, _arguments} = ast) do
     ast
-    |> Code.postwalk(&find_dependent_modules/2)
+    |> Credo.Code.postwalk(&find_dependent_modules/2)
     |> Enum.uniq()
   end
 


  def def_names_with_op({:defmodule, _, _arguments} = ast, arity) do
    ast
    |> Code.postwalk(&collect_defs/2)
    |> Enum.map(&def_name_with_op(&1, arity))
    |> Enum.reject(&is_nil/1)
    |> Enum.uniq()


  def def_names({:defmodule, _, _arguments} = ast) do
    ast
    |> Credo.Code.postwalk(&collect_defs/2)
    |> Enum.map(&def_name/1)
    |> Enum.uniq()
  end
