Why is urlpath passed as a list to open_files if it can be already a list?

[wachsylon]

The fsspec.open command allows urlpath to be a list. But a few lines later, urlpath is passed as a list. If it is already a list, it becomes a list of lists. I ran into problems with this:

File /work/bm1344/conda-envs/py_312/lib/python3.12/site-packages/fsspec/core.py:487, in open(urlpath, mode, compression, encoding, errors, protocol, newline, expand, **kwargs)
    429 """Given a path or paths, return one ``OpenFile`` object.
    430 
    431 Parameters
   (...)
    484   https://filesystem-spec.readthedocs.io/en/latest/api.html#other-known-implementations
    485 """
    486 expand = DEFAULT_EXPAND if expand is None else expand
--> 487 out = open_files(
    488     urlpath=[urlpath],
    489     mode=mode,
    490     compression=compression,
    491     encoding=encoding,
    492     errors=errors,
    493     protocol=protocol,
    494     newline=newline,
    495     expand=expand,
    496     **kwargs,
    497 )
    498 if not out:
    499     raise FileNotFoundError(urlpath)

File /work/bm1344/conda-envs/py_312/lib/python3.12/site-packages/fsspec/core.py:295, in open_files(urlpath, mode, compression, encoding, errors, name_function, num, protocol, newline, auto_mkdir, expand, **kwargs)
    216 def open_files(
    217     urlpath,
    218     mode="rb",
   (...)
    228     **kwargs,
    229 ):
    230     """Given a path or paths, return a list of ``OpenFile`` objects.
    231 
    232     For writing, a str path must contain the "*" character, which will be filled
   (...)
    293       https://filesystem-spec.readthedocs.io/en/latest/api.html#other-known-implementations
    294     """
--> 295     fs, fs_token, paths = get_fs_token_paths(
    296         urlpath,
    297         mode,
    298         num=num,
    299         name_function=name_function,
    300         storage_options=kwargs,
    301         protocol=protocol,
    302         expand=expand,
    303     )
    304     if fs.protocol == "file":
    305         fs.auto_mkdir = auto_mkdir

File /work/bm1344/conda-envs/py_312/lib/python3.12/site-packages/fsspec/core.py:651, in get_fs_token_paths(urlpath, mode, num, name_function, storage_options, protocol, expand)
    649 if protocol:
    650     storage_options["protocol"] = protocol
--> 651 chain = _un_chain(urlpath0, storage_options or {})
    652 inkwargs = {}
    653 # Reverse iterate the chain, creating a nested target_* structure

File /work/bm1344/conda-envs/py_312/lib/python3.12/site-packages/fsspec/core.py:343, in _un_chain(path, kwargs)
    341 kwargs = kwargs.copy()
    342 for bit in reversed(bits):
--> 343     protocol = kwargs.pop("protocol", None) or split_protocol(bit)[0] or "file"
    344     cls = get_filesystem_class(protocol)
    345     extra_kwargs = cls._get_kwargs_from_urls(bit)

File /work/bm1344/conda-envs/py_312/lib/python3.12/site-packages/fsspec/core.py:552, in split_protocol(urlpath)
    549     if len(protocol) > 1:
    550         # excludes Windows paths
    551         return protocol, path
--> 552 if urlpath.startswith("data:"):
    553     return urlpath.split(":", 1)
    554 return None, urlpath

AttributeError: 'list' object has no attribute 'startswith'