human
I wrote the below code

    if (file is None):
        from sys import stdout
        file = stdout
    def debug_rl(*args, **kwargs):
        expr = args[0]
        result = rule(*args, **kwargs)
        if (result != expr):
            file.write(('Rule:    %s\n' % get_function_name(rule)))
            file.write(('In:            %s\nOut:        %s\n\n' % (expr, result)))
        return result
    return debug_rl

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

def debug(rule, file=None):