diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 6cd2c4cb61b..49e3901aa7b 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -674,15 +674,12 @@ let pythonPackages = python.modules // rec {
 
     configureFlags = "--with-python=${python}";
 
-    postConfigure = let
-      changeIconv = "-e s:^iconv_includes.*:iconv_includes=r'${pkgs.libxml2.libiconv}':";
-    in
-      ''
-        cd python
-        sed -i setup.py \
-            -e "s:^ROOT.*:ROOT = r'${pkgs.libxml2}':" \
-            ${if pkgs.libxml2.libiconv != null then changeIconv else ""}
-      '';
+    postConfigure = ''
+      cd python
+      sed -i setup.py \
+          -e "s:^ROOT.*:ROOT = r'${pkgs.libxml2}':" \
+          -e "s:^iconv_includes.*:iconv_includes= r'${pkgs.libxml2.libiconv}':"
+    '';
 
     # has no tests
     doCheck = false;