human
I wrote the below code

    if (not file):
        from sys import stdout
        file = stdout
    def write(brl, expr, result):
        file.write(('Rule:    %s\n' % get_function_name(brl)))
        file.write(('In:    %s\nOut:    %s\n\n' % (expr, result)))
    return onaction(brule, write)

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

def debug(brule, file=None):