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

    def _apply(filter_, stream):
        for token in filter_.filter(lexer, stream):
            (yield token)
    for filter_ in filters:
        stream = _apply(filter_, stream)
    return stream

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

def apply_filters(stream, filters, lexer=None):