Get locale and domain group membership from current user without AD powershell module

Get-Groups.ps1

function Get-Groups {
    Param(
        [string]$isMember
    )
    
    if($isMember)
    {
        $mytoken = [System.Security.Principal.WindowsIdentity]::GetCurrent()
        $me = New-Object System.Security.Principal.WindowsPrincipal($mytoken)
        return $me.IsInRole($isMember)
    }
    else
    {
        $user_token = [System.Security.Principal.WindowsIdentity]::GetCurrent()
        $groups = New-Object System.Collections.ArrayList
        foreach($group in $user_token.Groups)
        {
           [void] $groups.Add( $group.Translate("System.Security.Principal.NTAccount") )
        }
        return $groups
    }
}