In Emacs 28, `python-shell-send-string' prints an additional newline
between the prompt and output (among other things, so you can tell
whether or not the inferior process is busy at any given time).

However, this interferes with ob-python, see e.g.
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=50514

The attached patch indicates how to solve the problem.  As a permanent
solution, I would suggest to replace org-babel-chomp and actually strip
whitespace from both ends of the string outputted from the Python
interpreter.  (IPython even has a configuration option to add extra
whitespace before or after the output.)