diff --git a/poetry.lock b/poetry.lock
index 5175c26..c625407 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -2721,4 +2721,4 @@ testing = ["big-O", "jaraco.functools", "jaraco.itertools", "more-itertools", "p
 [metadata]
 lock-version = "2.0"
 python-versions = "^3.8.1"
-content-hash = "0fe1d4585fbb1f8ccf4b288dfc93f24cb9c9f3ef3b949a571811e5271870e87a"
+content-hash = "222b06dabce13c6509be062d9bf0b5341894e38aadc61ae94307feb436932833"
diff --git a/pyproject.toml b/pyproject.toml
index b5c7c09..32b64a7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "cassini"
-version = "0.2.0-alpha2"
+version = "0.2.0a3"
 description = "A tool to structure experimental work, data and analysis using Jupyter Lab."
 authors = ["0Hughman0 <rammers2@hotmail.co.uk>"]
 license = "GPL-3.0-only"
@@ -11,6 +11,7 @@ python = "^3.8.1"
 pandas = "^1.0"
 ipywidgets = "^7.5"
 jupyterlab = "^4.0.0"
+typing-extensions = "^4.7.1"
 
 [tool.poetry.group.dev.dependencies]
 pytest = "^5.4"