diff --git a/day1/run.py b/day1/run.py
index 4a312bb..a115614 100644
--- a/day1/run.py
+++ b/day1/run.py
@@ -1,4 +1,4 @@
-from typing import List, Dict
+from typing import List
 
 EXAMPLE = """
 3   4
diff --git a/flake.nix b/flake.nix
index 2aef058..665d2b7 100644
--- a/flake.nix
+++ b/flake.nix
@@ -20,6 +20,7 @@
           python = pkgs.${system}.python3;
           pythonEnv = python.withPackages (
             ps: with ps; [
+              flake8
               isort
               mypy
             ]