diff --git a/pkgs/development/python-modules/FormEncode/default.nix b/pkgs/development/python-modules/FormEncode/default.nix
new file mode 100644
index 000000000000..f0ccead6059c
--- /dev/null
+++ b/pkgs/development/python-modules/FormEncode/default.nix
@@ -0,0 +1,32 @@
+{ stdenv, buildPythonPackage, fetchPypi, dns, pycountry, nose }:
+
+buildPythonPackage rec {
+  pname = "FormEncode";
+  version = "1.3.0";
+  name = "${pname}-${version}";
+
+  src = fetchPypi {
+    inherit pname version;
+    extension = "zip";
+    sha256 = "0y5gywq0l79l85ylr55p4xy0h921zgmfw6zmrvlh83aa4j074xg6";
+  };
+
+  buildInputs = [ dns pycountry nose ];
+
+  patchPhase = ''
+    # dnspython3 has been superseded, see its PyPI page
+    substituteInPlace setup.py --replace dnspython3 dnspython
+  '';
+
+  preCheck = ''
+    # two tests require dns resolving
+    sed -i 's/test_cyrillic_email/noop/' formencode/tests/test_email.py
+    sed -i 's/test_unicode_ascii_subgroup/noop/' formencode/tests/test_email.py
+  '';
+
+  meta = with stdenv.lib; {
+    description = "FormEncode validates and converts nested structures";
+    homepage = "http://formencode.org";
+    license = licenses.mit;
+  };
+}
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index c5d685bbd301..6a1b3365cc6f 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -15957,30 +15957,7 @@ in {
     '';
   };
 
-  FormEncode = buildPythonPackage rec {
-    name = "FormEncode-${version}";
-    version = "1.3.0";
-
-    src = pkgs.fetchurl {
-      url = "mirror://pypi/F/FormEncode/${name}.zip";
-      sha256 = "0y5gywq0l79l85ylr55p4xy0h921zgmfw6zmrvlh83aa4j074xg6";
-    };
-
-    buildInputs = with self; [
-      dns pycountry nose
-    ];
-
-    preCheck = ''
-      # two tests require dns resolving
-      sed -i 's/test_cyrillic_email/noop/' formencode/tests/test_email.py
-      sed -i 's/test_unicode_ascii_subgroup/noop/' formencode/tests/test_email.py
-    '';
-
-    meta = with stdenv.lib; {
-      description = "FormEncode validates and converts nested structures";
-      homepage = "http://formencode.org";
-    };
-  };
+  FormEncode = callPackage ../development/python-modules/FormEncode { };
 
   pycountry = buildPythonPackage rec {
     name = "pycountry-${version}";