'Function used internally to send static files from the static
folder to the browser.
.. versionadded:: 0.5'

def send_static_file(self, filename):

    if (not self.has_static_folder):
        raise RuntimeError('No    static    folder    for    this    object')
    cache_timeout = self.get_send_file_max_age(filename)
    return send_from_directory(self.static_folder, filename, cache_timeout=cache_timeout)
