'Checks if there exists a RewriteRule directive in vhost
:param vhost: vhost to check
:type vhost: :class:`~certbot_apache.obj.VirtualHost`
:returns: True if a RewriteRule directive exists.
:rtype: bool'

def _is_rewrite_exists(self, vhost):

    rewrite_path = self.parser.find_dir('RewriteRule', None, start=vhost.path)
    return bool(rewrite_path)
