diff --git a/pkgs/development/python-modules/pendulum/default.nix b/pkgs/development/python-modules/pendulum/default.nix
index c658928b431..0b57205d6ac 100644
--- a/pkgs/development/python-modules/pendulum/default.nix
+++ b/pkgs/development/python-modules/pendulum/default.nix
@@ -1,10 +1,18 @@
 { lib, fetchPypi, buildPythonPackage, pythonOlder
-, dateutil, pytzdata, typing }:
+, dateutil, pytzdata, typing
+, poetry-core
+}:
 
 buildPythonPackage rec {
   pname = "pendulum";
   version = "2.1.2";
 
+  format = "pyproject";
+
+  nativeBuildInputs = [
+    poetry-core
+  ];
+
   src = fetchPypi {
     inherit pname version;
     sha256 = "b06a0ca1bfe41c990bbf0c029f0b6501a7f2ec4e38bfec730712015e8860f207";