def get_shell_name(shell_obj):
    """
    This ridiculously simple function is enough to determine
    the receiving shell type for meterpreter upgrade.
    """
    if shell_obj.system_os == "linux":
        if "ssl" in shell_obj.short_name: 
            return "ssl"
        else:
            return "bash"
    if shell_obj.system_os == "windows":
        if "powershell" in shell_obj.short_name:
            return "powershell"
        else:
            return "cmd"