Second sentence of name-or-flags explanation of argparse.ArgumentParser.add_argument() in ja lang. is:

> そのため、add_argument() の第1引数は、フラグのリストか、シンプルな引数名のどちらかになります。
#[1]

while its original English is:

> The first arguments passed to add_argument() must therefore be either a series of flags, or a simple argument name.
# [2]

If I translate Japanese language one back to English, it'd be something:

The first argument passed to add_argument() must therefore be either a list of flags, or a simple argument name.

Japanese one's explanation means, name-or-flags could be either
- "name"
- ["-f", "--flag"]

So, Japanese translation could be improved to clarify that name-of-flags (i.e. first argument*s*) could be either name or *series* (not list) of flags.

Note that, following sentences in the doc have many supporting explanations, and also, there is argparse HOWTO doc with many examples, so this is not critical issue at all.

[1] https://docs.python.org/ja/3/library/argparse.html#name-or-flags
[2] https://docs.python.org/3/library/argparse.html#name-or-flags

Japanese translation is tracked as part of GitHub issues at https://github.com/python/python-docs-ja .