diff --git a/Formula/docker-cloud.rb b/Formula/docker-cloud.rb
index 4cc64820a7..5bc77b94bc 100644
--- a/Formula/docker-cloud.rb
+++ b/Formula/docker-cloud.rb
@@ -13,7 +13,7 @@ class DockerCloud < Formula
   end
 
   depends_on "libyaml"
-  depends_on "python@2"
+  depends_on "python@2" # does not support Python 3
 
   resource "ago" do
     url "https://files.pythonhosted.org/packages/83/1a/17e89f0be2cf69e17fbc96012bd6a2bf6d88a8fd3ac79854cc7007971943/ago-0.0.9.tar.gz"