code: function initialize (provider, configuration) {
    configuration.passReqToCallback = true
    configuration.path = provider.callbackUrl
    configuration.callbackUrl = provider.callbackUrl
  
    if (typeof configuration.cert === 'string') {
      try {
        configuration.cert = fs.readFileSync(configuration.cert, 'utf-8')
      } catch (err) {}
    }
  
    return new SAMLStrategy(configuration, verifier(provider, configuration))
  }
docs: Initialize