def str2time(s):
    """Takes a string of the format "hh:mm:ss" and converts it to an integer
value of the seconds since the start of the day.

    Parameters
    ----------
    s : str
        Time, in the format "hh:mm:ss".

    Returns
    -------
    t : int
        Time, in the seconds since the start of the day.
    """

    #Initialisations
    s_list = list(s)
    
    for i in range(len(s_list)):
        if s_list[i] == ":":
            continue
        s_list[i] = int(s_list[i])
    
    t = ((s_list[0]*10 + s_list[1])*3600 + (s_list[3]*10 + s_list[4])*60 
+ s_list[6]*10 + s_list[7])

    return t