customer_data_app doesn't run on < 3.12

(VENV-dev311) masen@asmbp21 customer_data_app % reflex run
─────────────────────────────────────────────────────────────────────────────────────── Initializing customer_data_app ────────────────────────────────────────────────────────────────────────────────────────
Warning: Your version (0.5.7) of reflex is out of date. Upgrade to 0.5.8 with 'pip install reflex --upgrade'
[14:31:19] Prior to reflex 0.4.0, rx.* components are based on Chakra UI. They are now based on Radix UI. To stick to Chakra UI, use rx.chakra.*.                                                console.py:104
                                                                                                                                                                                                 console.py:104
           Run `reflex script keep-chakra` to automatically update your app.                                                                                                                     console.py:104
                                                                                                                                                                                                 console.py:104
           For more details, please see https://reflex.dev/blog/2024-02-16-reflex-v0.4.0/                                                                                                        console.py:104
           Initializing the web directory.                                                                                                                                                       console.py:104
Success: Initialized customer_data_app
Info: The frontend will run on port 3002.
Info: The backend will run on port 8002.
Info: Overriding config value frontend_port with env var FRONTEND_PORT=3002
Info: Overriding config value backend_port with env var BACKEND_PORT=8002
───────────────────────────────────────────────────────────────────────────────────────────── Starting Reflex App ─────────────────────────────────────────────────────────────────────────────────────────────
Warning: Your version (0.5.7) of reflex is out of date. Upgrade to 0.5.8 with 'pip install reflex --upgrade'
Traceback (most recent call last):
  File "/Users/masen/code/reflex-dev/VENV-dev311/bin/reflex", line 8, in <module>
    sys.exit(cli())
             ^^^^^
  File "/Users/masen/code/reflex-dev/VENV-dev311/lib/python3.11/site-packages/typer/main.py", line 326, in __call__
    raise e
  File "/Users/masen/code/reflex-dev/VENV-dev311/lib/python3.11/site-packages/typer/main.py", line 309, in __call__
    return get_command(self)(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-dev311/lib/python3.11/site-packages/click/core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-dev311/lib/python3.11/site-packages/typer/core.py", line 723, in main
    return _main(
           ^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-dev311/lib/python3.11/site-packages/typer/core.py", line 193, in _main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-dev311/lib/python3.11/site-packages/click/core.py", line 1688, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-dev311/lib/python3.11/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-dev311/lib/python3.11/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-dev311/lib/python3.11/site-packages/typer/main.py", line 692, in wrapper
    return callback(**use_params)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/reflex/reflex/reflex.py", line 287, in run
    _run(env, frontend, backend, frontend_port, backend_port, backend_host, loglevel)
  File "/Users/masen/code/reflex-dev/reflex/reflex/reflex.py", line 213, in _run
    prerequisites.get_compiled_app()
  File "/Users/masen/code/reflex-dev/reflex/reflex/utils/prerequisites.py", line 289, in get_compiled_app
    app_module = get_app(reload=reload)
                 ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/reflex/reflex/utils/prerequisites.py", line 262, in get_app
    app = __import__(module, fromlist=(constants.CompileVars.APP,))
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/reflex-examples/customer_data_app/customer_data_app/customer_data_app.py", line 4, in <module>
    from .backend.backend import State
  File "/Users/masen/code/reflex-dev/reflex-examples/customer_data_app/customer_data_app/backend/backend.py", line 148
    return rx._x.toast.info(f"User {self.current_user["name"]} has been added.", variant="outline", position="bottom-right")
                                                       ^^^^
SyntaxError: f-string: unmatched '['
reflex-dev / reflex-examples

customer_data_app doesn't run on < 3.12 #250
