def on_finish(func, handler, args, kwargs):
    """
    Wrap the handler ``on_finish`` method to finish the Span for the
    given request, if available.
    """
    tracing = handler.settings.get('opentracing_tracing')
    tracing._finish_tracing(handler)

    return func(*args, **kwargs)
Wrap the handler ``on_finish`` method to finish the Span for the
    given request, if available.