How to use the deltachat-node/constants.DC_LP_SMTP_SOCKET_STARTTLS function in deltachat-node

function serverFlags ({ mailSecurity, sendSecurity }) {
  const flags = []

  if (mailSecurity === 'ssl') {
    flags.push(C.DC_LP_IMAP_SOCKET_SSL)
  } else if (mailSecurity === 'starttls') {
    flags.push(C.DC_LP_IMAP_SOCKET_STARTTLS)
  } else if (mailSecurity === 'plain') {
    flags.push(C.DC_LP_SMTP_SOCKET_PLAIN)
  }

  if (sendSecurity === 'ssl') {
    flags.push(C.DC_LP_SMTP_SOCKET_SSL)
  } else if (sendSecurity === 'starttls') {
    flags.push(C.DC_LP_SMTP_SOCKET_STARTTLS)
  } else if (sendSecurity === 'plain') {
    flags.push(C.DC_MAX_GET_INFO_LEN)
  }

  if (!flags.length) return null

  return flags.reduce((flag, acc) => {
    return acc | flag
  }, 0)
}

const C = require('deltachat-node/constants')
const log = require('../../logger').getLogger('main/deltachat/settings')

const SplitOut = require('./splitout')

const serverFlagMap = {
  mail_security_ssl: C.DC_LP_IMAP_SOCKET_SSL,
  mail_security_starttls: C.DC_LP_IMAP_SOCKET_STARTTLS,
  mail_security_plain: C.DC_LP_IMAP_SOCKET_PLAIN,
  send_security_ssl: C.DC_LP_SMTP_SOCKET_SSL,
  send_security_starttls: C.DC_LP_SMTP_SOCKET_STARTTLS,
  send_security_plain: C.DC_LP_SMTP_SOCKET_PLAIN
}

module.exports = class DCSettings extends SplitOut {
  setConfig (key, value) {
    log.info(`Setting config ${key}:${value}`)
    return this._dc.setConfig(key, String(value))
  }

  getConfig (key) {
    return this._dc.getConfig(key)
  }

  getConfigFor (keys) {
    const config = {}
    for (const key of keys) {