def warning_check_1(Vcell, I_Warning, I, warning_flag):
    """
    Check Vcell is negative or not.

    :param Vcell: Vcell of FC voltage
    :type Vcell : float
    :param I_Warning: first I of negative range
    :type I_Warning : float
    :param I: test current
    :type I : float
    :param warning_flag: input warning flag
    :type warning_flag : bool
    :return:  update warning_flag and I_Warning [bool,float]
    """
    if not warning_flag:
        try:
            if Vcell < 0:
                return [True, I]
            return [False, I]
        except Exception:
            return [False, I]
    else:
        return [True, I_Warning]
