'Used by session backends to determine if a ``Set-Cookie`` header
should be set for this session cookie for this response. If the session
has been modified, the cookie is set. If the session is permanent and
the ``SESSION_REFRESH_EACH_REQUEST`` config is true, the cookie is
always set.
This check is usually skipped if the session was deleted.
.. versionadded:: 0.11'

def should_set_cookie(self, app, session):

    return (session.modified or (session.permanent and app.config['SESSION_REFRESH_EACH_REQUEST']))
