diff --git a/Makefile b/Makefile
index 89eefaa..de49d07 100644
--- a/Makefile
+++ b/Makefile
@@ -61,6 +61,9 @@ format:
 	black --line-length 100 tests
 	black --line-length 100 examples/*.ipynb
 
+format_notebook:
+	black --line-length 100 /workdir/*.ipynb
+
 init: setup tests
 
 linter:
diff --git a/examples/calibration-demo.ipynb b/examples/calibration-demo.ipynb
index 21ad500..19cdf73 100644
--- a/examples/calibration-demo.ipynb
+++ b/examples/calibration-demo.ipynb
@@ -256,7 +256,7 @@
     "    label=\"real density\",\n",
     ")\n",
     "plt.xlabel(\"Distance (m)\", size=fontsize)\n",
-    "plt.ylabel(\"Density (kg/m$^2$)\", size=fontsize);\n",
+    "plt.ylabel(\"Density (kg/m$^2$)\", size=fontsize)\n",
     "plt.savefig(\"figures/density_profile.png\")"
    ]
   },