tst: raise UserWarning

Author: mmcky

lectures/aiyagari.md

@@ -26,6 +26,11 @@ kernelspec:
 :depth: 2
 ```
 
+```{code-cell} ipython3
+from warnings import UserWarning
+raise UserWarning("TEST")
+```
+
 In addition to what's in Anaconda, this lecture will need the following libraries:
 
 ```{code-cell} ipython3