diff --git a/demo/completed-demo/yarn.lock b/demo/completed-demo/yarn.lock
index c662baf..bc8ba16 100644
--- a/demo/completed-demo/yarn.lock
+++ b/demo/completed-demo/yarn.lock
@@ -194,6 +194,19 @@
     codemirror "~5.53.2"
     react "~16.9.0"
 
+"@jupyterlab/coreutils@^4.0.0", "@jupyterlab/coreutils@^4.3.0":
+  version "4.3.0"
+  resolved "https://registry.yarnpkg.com/@jupyterlab/coreutils/-/coreutils-4.3.0.tgz#319926678993d93da08962455c68ee508ed71071"
+  integrity sha512-kqbE2BWSMPvYtkfIVtW9xO/li09rA//cHRvkaMdZ4nxPR4D5v7Qh2dTsc62HwBMLNwOumNp8kWv89pyjFbm8yw==
+  dependencies:
+    "@lumino/coreutils" "^1.4.2"
+    "@lumino/disposable" "^1.3.5"
+    "@lumino/signaling" "^1.3.5"
+    minimist "~1.2.0"
+    moment "^2.24.0"
+    path-posix "~1.0.0"
+    url-parse "~1.4.7"
+
 "@jupyterlab/coreutils@^4.2.4":
   version "4.2.4"
   resolved "https://registry.yarnpkg.com/@jupyterlab/coreutils/-/coreutils-4.2.4.tgz#f02ca96f435f94fa049748d2afe0921240fb502d"
@@ -278,6 +291,13 @@
   dependencies:
     "@lumino/coreutils" "^1.4.2"
 
+"@jupyterlab/nbformat@^2.3.0":
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/@jupyterlab/nbformat/-/nbformat-2.3.0.tgz#8ab12436fbc0fb817374abd272edc5cbf6bf24f8"
+  integrity sha512-vQ9aZlvss5iRJYnFDzdF6eCsXIdM0/gzguXKkJ06cpG6E5c3A4GmdFtN8IrgUk6VDPpjTT49ptyfBxMZIfCIwg==
+  dependencies:
+    "@lumino/coreutils" "^1.4.2"
+
 "@jupyterlab/notebook@^2.0.0":
   version "2.2.6"
   resolved "https://registry.yarnpkg.com/@jupyterlab/notebook/-/notebook-2.2.6.tgz#06e180f294079b733d483e1bdf4ab06dcbcab943"
@@ -316,6 +336,17 @@
     "@lumino/messaging" "^1.3.3"
     "@lumino/signaling" "^1.3.5"
 
+"@jupyterlab/observables@^3.3.0":
+  version "3.3.0"
+  resolved "https://registry.yarnpkg.com/@jupyterlab/observables/-/observables-3.3.0.tgz#2ae959dc1c20b712515f6afef24972ae562ca6b4"
+  integrity sha512-YdXuVSRbkU43NuRTwD7gwXDV48HT8reJt3KL5lTChx/ZkDMWh8Au2IQHHJBbO+WiyicO9HDT0fll5fYCAATVdw==
+  dependencies:
+    "@lumino/algorithm" "^1.2.3"
+    "@lumino/coreutils" "^1.4.2"
+    "@lumino/disposable" "^1.3.5"
+    "@lumino/messaging" "^1.3.3"
+    "@lumino/signaling" "^1.3.5"
+
 "@jupyterlab/outputarea@^2.2.3":
   version "2.2.3"
   resolved "https://registry.yarnpkg.com/@jupyterlab/outputarea/-/outputarea-2.2.3.tgz#1be7a190a060234b9fb684f5bcfdbc283739da40"
@@ -363,6 +394,24 @@
     lodash.escape "^4.0.1"
     marked "^0.8.0"
 
+"@jupyterlab/services@^5.0.0":
+  version "5.3.0"
+  resolved "https://registry.yarnpkg.com/@jupyterlab/services/-/services-5.3.0.tgz#812166e2f59d53efbae6e86455ae7a8e7ebdb1f5"
+  integrity sha512-aAKdeXr7nzZt+0ukqh+uljvhiO7aDkoWQpIzJgMjIoggL2KdqLc0lzO8lzgglIx6D+BRod5nCeouAbt4i2Ju5Q==
+  dependencies:
+    "@jupyterlab/coreutils" "^4.3.0"
+    "@jupyterlab/nbformat" "^2.3.0"
+    "@jupyterlab/observables" "^3.3.0"
+    "@jupyterlab/settingregistry" "^2.3.0"
+    "@jupyterlab/statedb" "^2.3.0"
+    "@lumino/algorithm" "^1.2.3"
+    "@lumino/coreutils" "^1.4.2"
+    "@lumino/disposable" "^1.3.5"
+    "@lumino/polling" "^1.1.1"
+    "@lumino/signaling" "^1.3.5"
+    node-fetch "^2.6.0"
+    ws "^7.2.0"
+
 "@jupyterlab/services@^5.2.4":
   version "5.2.4"
   resolved "https://registry.yarnpkg.com/@jupyterlab/services/-/services-5.2.4.tgz#e9331a98db435abc83ffa902799df59fe6b9c15c"
@@ -394,6 +443,19 @@
     ajv "^6.10.2"
     json5 "^2.1.1"
 
+"@jupyterlab/settingregistry@^2.3.0":
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/@jupyterlab/settingregistry/-/settingregistry-2.3.0.tgz#7bad755cb2c125d8aaf58f664d9840eb0d9db0db"
+  integrity sha512-3sZrDGojldPkNg7oM4+x4TH94V3wIBQInunak2tlS8G9AyDEennC13dNN9KKPkLw2SQI52pX6/Xt2yRtW/IGgQ==
+  dependencies:
+    "@jupyterlab/statedb" "^2.3.0"
+    "@lumino/commands" "^1.10.1"
+    "@lumino/coreutils" "^1.4.2"
+    "@lumino/disposable" "^1.3.5"
+    "@lumino/signaling" "^1.3.5"
+    ajv "^6.10.2"
+    json5 "^2.1.1"
+
 "@jupyterlab/statedb@^2.2.4":
   version "2.2.4"
   resolved "https://registry.yarnpkg.com/@jupyterlab/statedb/-/statedb-2.2.4.tgz#674d7b59b51c6b2f76e8557eb2ff64797f9a85e9"
@@ -405,6 +467,17 @@
     "@lumino/properties" "^1.1.6"
     "@lumino/signaling" "^1.3.5"
 
+"@jupyterlab/statedb@^2.3.0":
+  version "2.3.0"
+  resolved "https://registry.yarnpkg.com/@jupyterlab/statedb/-/statedb-2.3.0.tgz#1b47d14e81ccd03e25ed94555019a76398a7e2c5"
+  integrity sha512-1QlWREUCxNhjOlsCdENSY10JiE3b7uVlxVCWqlwM58j1QA9/CzYYRzHWwBL6yJXHSSW3MlaXKqQ4xDCVvjR2hg==
+  dependencies:
+    "@lumino/commands" "^1.10.1"
+    "@lumino/coreutils" "^1.4.2"
+    "@lumino/disposable" "^1.3.5"
+    "@lumino/properties" "^1.1.6"
+    "@lumino/signaling" "^1.3.5"
+
 "@jupyterlab/statusbar@^2.2.3":
   version "2.2.3"
   resolved "https://registry.yarnpkg.com/@jupyterlab/statusbar/-/statusbar-2.2.3.tgz#27f65e4e6303732f4eb56d1d8d1486d55f0dc68a"
@@ -2102,9 +2175,9 @@ write@1.0.3:
     mkdirp "^0.5.1"
 
 ws@^7.2.0:
-  version "7.3.1"
-  resolved "https://registry.yarnpkg.com/ws/-/ws-7.3.1.tgz#d0547bf67f7ce4f12a72dfe31262c68d7dc551c8"
-  integrity sha512-D3RuNkynyHmEJIpD2qrgVkc9DQ23OrN/moAwZX4L8DfvszsJxpjQuUq3LMx6HoYji9fbIOBY18XWBsAux1ZZUA==
+  version "7.4.6"
+  resolved "https://registry.yarnpkg.com/ws/-/ws-7.4.6.tgz#5654ca8ecdeee47c33a9a4bf6d28e2be2980377c"
+  integrity sha512-YmhHDO4MzaDLB+M9ym/mDA5z0naX8j7SIlT8f8z+I0VtzsRbekxEutHSme7NPS2qE8StCYQNUnfWdXta/Yu85A==
 
 xtend@^4.0.1:
   version "4.0.2"