Change kernel to be accept a list of kernels

List of kernel paths are formatted into JUPYTER_PATH environment
variable

jupyter.nix

@@ -1,20 +1,25 @@
 {
-  pkgs,
+  mkShellNoCC,
-  kernel,
+  python3,
-  python ? pkgs.python3,
+  kernels ? [],
+  extraPackages ? (ps: []),
 }:
-pkgs.mkShellNoCC {
+mkShellNoCC {
   nativeBuildInputs = [
-    (python.withPackages (ps:
+    (python3.withPackages (ps:
-      with ps; [
+      with ps;
+        [
           jupyterlab
           jupyterlab-git
           nbdime
           nbconvert
+          python-lsp-server
           (ps.callPackage ./catppuccin_jupyterlab {})
-      ]))
+        ]
+        ++ (extraPackages ps)))
   ];
-  shellHook = ''
+  shellHook = with builtins; let
-    export JUPYTER_PATH=${kernel}
+    kernelString = foldl' (x: y: ":" + (toString y) + x) "" kernels;
-  '';
+    pathString = substring 1 (stringLength kernelString) kernelString;
+  in "export JUPYTER_PATH=${pathString}";
 }