human
I wrote the below code

    def repl(match):
        m = match.group(0).strip('${}')
        return replacements.get(m.lower(), match.group(0))
    return re.sub('(\\$\\w+\\b|\\$\\{\\w+\\})', repl, path)

What's a good function header?

Here's a good function header?
assistant
#Here's a good function header.

def substitute_config_variables(path):