How to close custome Tab which open by tiktok customTabsIntent

[reachzhai]

    private fun launchChromeTab(authRequest: AuthRequest): Boolean {
        if (!authRequest.validate()) {
            return false
        }
        val builder = CustomTabsIntent.Builder()
        val customTabsIntent = builder.build()
        customTabsIntent.launchUrl(
            activity,
            Uri.parse(
                WebAuthHelper.composeLoadUrl(
                    activity,
                    authRequest,
                    activity.packageName,
                )
            )
        )
        return true
    }

[youngKimTikTok]

You can close the tab by going to the custom tab and tapping the 'X' button in the upper-left of your screen (the location of the button is subject to the device's model).
If this does not answer your question, could you please clarify what you mean by "closing the custom tab"?