FYI, Min RK commented on the IPython issue:
https://github.com/ipython/ipython/issues/1109#issuecomment-3071470

In short, 
shlex.shlex('blob f(" ")', posix=False)
fails, whereas 
shlex.shlex('blob f( " ")', posix=False)

"The problem appears to be that Python source obviously doesn't sit well with non-posix whitespace-split shlex. [...] if you lead all your open-quotes with whitespace, you should be fine (works for all given examples, at least). [...] I have no idea whether this is a Python bug or not, since I don't know what the reference standard is, but this is definitely an IPython bug.  We should not be trying to use shlex to parse Python code as if it were command-line arguments."