def get_sec(time_str):
    """
    Reads a string of time
    returns the seconds of it in numerical form
    Parameters
    ---------
    time_str : a str object
             Contains the time in MIN
    Returns
    -------
        : int
             Contains the time in seconds
    """
    m, s = time_str.split(":")
    return int(m) * 60 + int(s)