human
I wrote the below code

    if (not isinstance(prefix, (tuple, list))):
        prefix = (prefix,)
    def f(msg):
        text = extractor(msg)
        for px in prefix:
            if text.startswith(px):
                chunks = text[len(px):].split(separator)
                return (chunks[0], ((chunks[1:],) if pass_args else ()))
        return ((None,),)
    return f

What's a good function header?
 Give me a Python code to fix = (prefix,)?
assistant
#Here is Python code to fix = (prefix,)
.

def by_command(extractor, prefix=('/',), separator='    ', pass_args=False):