python3Packages.Pweave: fix build

pkgs/development/python-modules/pweave/default.nix

@@ -7,6 +7,7 @@
 , nbconvert
 , markdown
 , isPy3k
+, ipykernel
 }:
 
 buildPythonPackage rec {
@@ -21,7 +22,7 @@ buildPythonPackage rec {
   disabled = !isPy3k;
 
   buildInputs = [ mock pkgs.glibcLocales ];
-  propagatedBuildInputs = [ matplotlib nbconvert markdown ];
+  propagatedBuildInputs = [ ipykernel matplotlib nbconvert markdown ];
 
   # fails due to trying to run CSS as test
   doCheck = false;