show output from python-shell-send-region

Question

Using python.el and ipython.exe (from Miniconda3), I'd like to highlight a portion of code and execute it in the associated inferior python buffer. Example:

#!/usr/bin/python3

myvar = 100+200
        ^^^^^^^ (this is my selected region)

If I use C-c C-c, it correctly sources the file. That's not what I want.

If I highlight the region as depicted above and use C-c C-r (python-shell-send-region), the entire line is executed, not just the region. That is, myvar should not be defined by this step. I'd like to send just the highlight region.

So I created an edited version of python-shell-buffer-substring, omitting the part that redefines start:

  (let* ((start (save-excursion
                  ;; Normalize start to the line beginning position.
                  (goto-char start)
                  (line-beginning-position)))

I also create my-python-shell-send-region, where the only difference is it calls my-python-shell-buffer-substring. This properly creates the substring

# -*- coding: utf-8 -*-

100+200

and sends it correctly to the inferior process. Except ... the output is inhibited (generally a good thing), and I'd like to see the output 300. I see the function python-shell-send-string-no-output, but I don't see a way to allow output when using *-send-string.

Q: how to allow the output, and/or is there a better mechanism for doing this?

(In the unrelated package ess, I use C-u C-c C-r for show-no-output, and C-c C-r when I want the output shown. I can deal with a reversal of this logic, that's not the issue for this question.)

(emacs-25.2.1 (x86_64-w64-mingw32) and ein-20171128.516)

EDIT

After some more digging (thanks wvxvw), I found that removing the inserted # -*- coding: utf-8 -*- line from the pasted string allowed the inferior process to print the output, but only on single-line regions. For instance:

#!/usr/bin/python3

myvar = 100+200
200+300

Highlighting just 100+200 produced the output 300, good. Highlighting from 100 through 300 on the next line, however, produced no output. If the highlighted string is on a single line and contains semicolon-delimited commands (e.g., 100+200;200+300), then the output from the last command is shown, nothing else (which is, I believe, correct behavior for python.) So the problem remains with multi-line regions.