diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8d46d7d..ede88c3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -47,7 +47,7 @@ jobs:
 
     strategy:
       matrix:
-        python-version: ["3.10"]
+        python-version: ["3.10", 3.13]
 
     steps:
     - name: Check out code
diff --git a/src/pyladoc/__init__.py b/src/pyladoc/__init__.py
index 2719c10..48788af 100644
--- a/src/pyladoc/__init__.py
+++ b/src/pyladoc/__init__.py
@@ -90,8 +90,9 @@ def _save_figure(fig: Figure, buff: io.BytesIO, figure_format: FFormat, font_fam
             yield ax.xaxis.label
             yield ax.yaxis.label
             yield from ax.get_xticklabels() + ax.get_yticklabels()
-            legend: Mpl_Legend = ax.get_legend()
+            legend = ax.get_legend()
             if legend:
+                assert isinstance(legend, Mpl_Legend)
                 yield from legend.get_texts()
 
     # Store current figure settings