PG Bug reporting form <noreply(at)postgresql(dot)org> writes:
> # Steps to Reproduce
> Install extension plpython3u
> Create function using data type numeric as an input, may be unique input or
> in combination with other data types.
> Use Function in query such as SELECT or UPDATE.
Hm. The given test case works fine for me, using python 3.7.4
on a Fedora 30 installation. I suspect some oddness in your
python installation, maybe there are unusual components in it?
regards, tom lane