diff --git a/default.nix b/default.nix
index 5166f55413648649c80272d6d0245c536633a8bd..18dba97f1f4b09fa44b7432035b43d7402f99274 100644
--- a/default.nix
+++ b/default.nix
@@ -53,11 +53,17 @@ in
       #   this another way, dependencies have undetected dependencies, easier
       #   to just use the wheel.
       collections-extended = "wheel";
+      # same as collections-extended
+      isort = "wheel";
 
       # From nixpkgs or sdist, fails with
       # cp: cannot stat 'benchmark/': No such file or directory
       # cp: cannot stat 'tests/': No such file or directory
       tomli = "wheel";
+
+      # repo re-org or something?
+      # find: ‘hypothesis-6.32.1/hypothesis-python’: No such file or directory
+      hypothesis = "wheel";
     };
   in
     rec {
diff --git a/setup.cfg b/setup.cfg
index 65fd066ca911486200be2dbf792e0d06cea458b6..fe4b45cdd2c4af526f1470c94be88bc13b101f47 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -53,6 +53,10 @@ install_requires =
     # install cross-platform.
     colorama
 
+    # Python 3 transition
+    six
+    future
+
 [options.extras_require]
 test = coverage; fixtures; testtools; hypothesis
 
diff --git a/shell.nix b/shell.nix
index 5f5d6489ec325e0b763159835b671b8e4b612784..023fc1bdb969c66f6b0d8da9d0c3b638396b96f1 100644
--- a/shell.nix
+++ b/shell.nix
@@ -6,7 +6,7 @@ let
   inherit (tests) pkgs;
 in
 pkgs.mkShell {
-  packages = [
+  buildInputs = [
     tests.python
     tests.lint-python
     pkgs.niv