What is wrong with the syntax of this simple Python list?

Question

Maybe I've gotten rusty with Python. Why is this not acceptable when pasted into a Python shell?

hdr_filenames = [
    "20210311_105300_HDR.jpg",
    "20210311_105306_HDR.jpg",
    "20210311_105310_HDR.jpg",
    "20210311_105314_HDR.jpg",
    "20210311_105341_HDR.jpg",    # order of last two have reversed exposures   
    "20210311_105323_HDR.jpg"
    ]

When this is copied to the prompt in an xterm running python3, I get (never mind the quaint retro term):

EDIT: silly of me to forget to report some basic obvious info: This is Python version 3.9.1, on Arch Linux updated about a month or so ago.

Answer 1

So, I don't have a complete answer here, but this has something to do with the new PEG parser that debuted in Python 3.9, because when I use it (it is the default parser on Python 3.9), I get the same error:

Python 3.9.1 (default, Dec 11 2020, 06:28:49)
[Clang 10.0.0 ] :: Anaconda, Inc. on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> hdr_filenames = [
    "20210311_105300_HDR.jpg",
    "20210311_105306_HDR.jpg",
    "20210311_105310_HDR.jpg",
    "20210311_105314_HDR.jpg",
    "20210311_105341_HDR.jpg",    # order of last two have reversed exposures
    "20210311_105323_HDR.jpg"
    ]
  File "<stdin>", line 1
        ]
         ^
SyntaxError: multiple statements found while compiling a single statement

BUT You can revert to the old, LL(1) parser by passing a command line option, an voila! No error:

(py39) juanarrivillaga@50-254-139-253-static % python -X oldparser
Python 3.9.1 (default, Dec 11 2020, 06:28:49)
[Clang 10.0.0 ] :: Anaconda, Inc. on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> hdr_filenames = [
    "20210311_105300_HDR.jpg",
    "20210311_105306_HDR.jpg",
    "20210311_105310_HDR.jpg",
    "20210311_105314_HDR.jpg",
    "20210311_105341_HDR.jpg",    # order of last two have reversed exposures
    "20210311_105323_HDR.jpg"
    ]
>>> exit()

For those interested, the relevant PEP 617 about the new parser.

EDIT

So, this no-longer seems to be a problem on Python 3.9.2 (the latest version currently, I believe). So perhaps upgrade?

Python 3.9.2 (default, Mar  3 2021, 11:58:52)
[Clang 10.0.0 ] :: Anaconda, Inc. on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> hdr_filenames = [
...     "20210311_105300_HDR.jpg",
...     "20210311_105306_HDR.jpg",
...     "20210311_105310_HDR.jpg",
...     "20210311_105314_HDR.jpg",
...     "20210311_105341_HDR.jpg",    # order of last two have reversed exposures
...     "20210311_105323_HDR.jpg"
...     ]
>>>