   def extract_stale([], _targets), do: []
 
   def extract_stale(sources, targets) do
-    stale_stream(sources, targets) |> Enum.to_list
+    stale_stream(sources, targets) |> Enum.to_list()
   end
 
   defp stale_stream(sources, targets) do
-    modified_target = targets |> Enum.map(&last_modified/1) |> Enum.min
-
-    Stream.filter(sources, fn(source) ->
+    modified_target = targets |> Enum.map(&last_modified/1) |> Enum.min()
+
+    Stream.filter(sources, fn source ->
       last_modified(source) > modified_target
     end)
   end

  end

  defp proxy_env do
    http_proxy  = System.get_env("HTTP_PROXY")  || System.get_env("http_proxy")
    https_proxy = System.get_env("HTTPS_PROXY") || System.get_env("https_proxy")
    no_proxy    = no_proxy_env() |> no_proxy_list()

    {proxy_setup(:http, http_proxy, no_proxy), proxy_setup(:https, https_proxy, no_proxy)}
  end

  end

  defp path_separator do
    case :os.type() do
      {:win32, _} -> ";"
      {:unix, _} -> ":"
    end
  end

