diff --git a/pkgs/development/python-modules/serverlessrepo/default.nix b/pkgs/development/python-modules/serverlessrepo/default.nix
index 7c89d9d1f8d9..c6795f172064 100644
--- a/pkgs/development/python-modules/serverlessrepo/default.nix
+++ b/pkgs/development/python-modules/serverlessrepo/default.nix
@@ -1,24 +1,13 @@
 { lib
-, python
+, buildPythonPackage
+, fetchPypi
+, pytest
+, boto3
+, six
+, pyyaml
+, mock
 }:
 
-let
-  py = python.override {
-    packageOverrides = self: super: {
-      pyyaml = super.pyyaml.overridePythonAttrs (oldAttrs: rec {
-        version = "3.12";
-        src = oldAttrs.src.override {
-          inherit version;
-          sha256 = "592766c6303207a20efc445587778322d7f73b161bd994f227adaa341ba212ab";
-        };
-      });
-    };
-  };
-
-in
-
-with py.pkgs;
-
 buildPythonPackage rec {
   pname = "serverlessrepo";
   version = "0.1.8";
@@ -40,6 +29,10 @@ buildPythonPackage rec {
     pytest tests/unit
   '';
 
+  postPatch = ''
+    substituteInPlace setup.py --replace "pyyaml~=3.12" "pyyaml~=5.1"
+  '';
+
   meta = with lib; {
     homepage = https://github.com/awslabs/aws-serverlessrepo-python;
     description = "Helpers for working with the AWS Serverless Application Repository";