human
Here's a good function header given the following:
I wrote the below code

    def maybe_censor(key, value, mask=(u'*' * 8)):
        if isinstance(value, Mapping):
            return filter_hidden_settings(value)
        if isinstance(key, string_t):
            if HIDDEN_SETTINGS.search(key):
                return mask
            elif (u'broker_url' in key.lower()):
                from kombu import Connection
                return Connection(value).as_uri(mask=mask)
            elif (u'backend' in key.lower()):
                return maybe_sanitize_url(value, mask=mask)
        return value
    return {k: maybe_censor(k, v) for (k, v) in items(conf)}

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

def filter_hidden_settings(conf):