'Include OCSP response in TLS handshake
:param str domain: domain to enable OCSP response for
:param chain_path: chain file path
:type chain_path: `str` or `None`'

def _enable_ocsp_stapling(self, domain, chain_path):

    vhost = self.choose_vhost(domain)
    if (self.version < (1, 3, 7)):
        raise errors.PluginError('Version    1.3.7    or    greater    of    nginx    is    needed    to    enable    OCSP    stapling')
    if (chain_path is None):
        raise errors.PluginError('--chain-path    is    required    to    enable    Online    Certificate    Status    Protocol    (OCSP)    stapling    on    nginx    >=    1.3.7.')
    stapling_directives = [['\n                ', 'ssl_trusted_certificate', '    ', chain_path], ['\n                ', 'ssl_stapling', '    ', 'on'], ['\n                ', 'ssl_stapling_verify', '    ', 'on'], ['\n']]
    try:
        self.parser.add_server_directives(vhost, stapling_directives, replace=False)
    except errors.MisconfigurationError as error:
        logger.debug(error)
        raise errors.PluginError('An    error    occurred    while    enabling    OCSP    stapling    for    {0}.'.format(vhost.names))
    self.save_notes += 'OCSP    Stapling    was    enabled    on    SSL    Vhost:    {0}.\n'.format(vhost.filep)
    self.save_notes += ' DCTB ssl_trusted_certificate    {0}\n'.format(chain_path)
    self.save_notes += ' DCTB ssl_stapling    on\n'
    self.save_notes += ' DCTB ssl_stapling_verify    on\n'
