Multiple sheets not support for shell user

[Martincaaa]

By importing xlsx2html in .py, multiple sheets feature can be called by using xlsx2html(a.xlsx,b.html,sheet=-1)
When trying to output the html file using shell command directly (python3 -m xlsx2html a.xlsx b.html,sheet=-1),
it returned msg: Usage: xlsx2html input.xlsx output.html.

I have tried using python3 -m xlsx2html a.xlsx b.html simply to get multiple sheet html, it returned one sheet cause sheet = None as default.