diff --git a/demo/completed-demo/yarn.lock b/demo/completed-demo/yarn.lock
index c662baf..889e5e0 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@^4.3.1":
+  version "4.3.1"
+  resolved "https://registry.yarnpkg.com/@jupyterlab/coreutils/-/coreutils-4.3.1.tgz#c0d677946a9c751edc96954998ad08dcadb918a3"
+  integrity sha512-WBwhPmK6VFAjNX7Y6a9JLUiJ2ldURZp/gbN3XsSFEGpZPSgt2UdTRWn60t6UayV1YE9bQy1TS2Pt97/fDDTudQ==
+  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@^2.3.1":
+  version "2.3.1"
+  resolved "https://registry.yarnpkg.com/@jupyterlab/nbformat/-/nbformat-2.3.1.tgz#a73a6ec2217202fdb8e09df040cd6c8b42d48dd6"
+  integrity sha512-hrMDoiO6Mz7J/19tcXsiboDOQHl/U1KiLhzuueZb2FVLiAe/D0lPHOAD+4H+yfaTrkSwsuej6l67DpZRwUpJBg==
+  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@^3.3.1":
+  version "3.3.1"
+  resolved "https://registry.yarnpkg.com/@jupyterlab/observables/-/observables-3.3.1.tgz#86ce39758944c7d1d67ee641683fa68713f2b893"
+  integrity sha512-Xj9JJMshvKbtnkUp5KE1BU7Hx8LvLDE+syfvbSepZidkYadMPg+bVToLinyyAAtnnZlXvOIGwAcJugHJWbvaaw==
+  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 "5.3.1"
+  resolved "https://registry.yarnpkg.com/@jupyterlab/services/-/services-5.3.1.tgz#5f6a3dd90347b7d0a4d6d3335ae20f296640d744"
+  integrity sha512-bV3UVihpeX5W5V57xLoL8gK0PVkvBeiSmHIlFEL2S8rCCDWLcyed7PoLnTe9eRvbCBZpZOEyqs9tk1zlQkQwqQ==
+  dependencies:
+    "@jupyterlab/coreutils" "^4.3.1"
+    "@jupyterlab/nbformat" "^2.3.1"
+    "@jupyterlab/observables" "^3.3.1"
+    "@jupyterlab/settingregistry" "^2.3.1"
+    "@jupyterlab/statedb" "^2.3.1"
+    "@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@^2.3.1":
+  version "2.3.1"
+  resolved "https://registry.yarnpkg.com/@jupyterlab/settingregistry/-/settingregistry-2.3.1.tgz#9821f3462285f82efdf8d7214b9ae60f3969ecbf"
+  integrity sha512-UeZObQ6pMkca1SSYzrmPKGwiRZdm6yuBf1Ab8Cv4cGBzVplFmUp8kHjbK/V+PSV9nhog/qlpUREHoy4jlMFxUA==
+  dependencies:
+    "@jupyterlab/statedb" "^2.3.1"
+    "@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@^2.3.1":
+  version "2.3.1"
+  resolved "https://registry.yarnpkg.com/@jupyterlab/statedb/-/statedb-2.3.1.tgz#c6a04d2c2f6c45a3e62a276e0cbe06a3fcb36d83"
+  integrity sha512-4f4hgSFg08sTIQjXlVOv93EGMAVxFOrZ4pk3RTyxnptfBboTvX/h9AmqE6REaNxi1KMwCXMeVO9gO+CFlFnFdA==
+  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"
@@ -706,9 +779,9 @@ astral-regex@^1.0.0:
   integrity sha512-+Ryf6g3BKoRc7jfp7ad8tM4TtMiaWvbF/1/sQcZPkkS7ag3D5nMBCe2UfOTONtAkaG0tO0ij3C5Lwmf1EiyjHg==
 
 balanced-match@^1.0.0:
-  version "1.0.0"
-  resolved "https://registry.yarnpkg.com/balanced-match/-/balanced-match-1.0.0.tgz#89b4d199ab2bee49de164ea02b89ce462d71b767"
-  integrity sha1-ibTRmasr7kneFk6gK4nORi1xt2c=
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/balanced-match/-/balanced-match-1.0.2.tgz#e83e3a7e3f300b34cb9d87f615fa0cbf357690ee"
+  integrity sha512-3oSeUO0TMV67hN1AmbXsK4yaqU7tjiHlbxRDZOpH0KW9+CeX4bRAaX0Anxt0tx2MrpRpWwQaPwIlISEJhYU5Pw==
 
 brace-expansion@^1.1.7:
   version "1.1.11"
@@ -794,7 +867,7 @@ color-name@~1.1.4:
 concat-map@0.0.1:
   version "0.0.1"
   resolved "https://registry.yarnpkg.com/concat-map/-/concat-map-0.0.1.tgz#d8a96bd77fd68df7793a73036a3ba0d5405d477b"
-  integrity sha1-2Klr13/Wjfd5OnMDajug1UBdR3s=
+  integrity sha512-/Srv4dswyQNBfohGpz9o6Yb3Gz3SrUDqBH5rTuhGR7ahtlbYKnVxw2bCFMRljaA7EXHaXZ8wsHdodFvbkhKmqg==
 
 create-react-context@^0.3.0:
   version "0.3.0"
@@ -1465,9 +1538,9 @@ mimic-fn@^2.1.0:
   integrity sha512-OqbOk5oEQeAZ8WXWydlu9HJjz9WVdEIvamMCcXmuqUYjTknH/sqsWvhQ3vgwKFRR1HpjvNBKQ37nbJgYzGqGcg==
 
 minimatch@^3.0.4:
-  version "3.0.4"
-  resolved "https://registry.yarnpkg.com/minimatch/-/minimatch-3.0.4.tgz#5166e286457f03306064be5497e8dbb0c3d32083"
-  integrity sha512-yJHVQEhyqPLUTgt9B83PXu6W3rx4MvvHvSUvToogpwoGDOUQ+yDrR0HRot+yOCdCO7u4hX3pWft6kWBBcqh0UA==
+  version "3.1.2"
+  resolved "https://registry.yarnpkg.com/minimatch/-/minimatch-3.1.2.tgz#19cd194bfd3e428f049a70817c038d89ab4be35b"
+  integrity sha512-J7p63hRiAjw1NDEww1W7i37+ByIrOWO5XQQAzZ3VOcL0PNybwpfmV/N05zFAzwQ9USyEcX6t3UO+K5aqBQOIHw==
   dependencies:
     brace-expansion "^1.1.7"