def _get_day_of_year(arg):
    """
    Get the day position in the year starting from 1
    
    Parameters
    ----------
    arg : tuple
    
    Returns
    -------
    int with the correct day of the year starting from 1
    """
    ml = [31,28,31,30,31,30,31,31,30,31,30,31]
    if arg[0]%4==0:
        ml[1] += 1
    i=1
    yday=0
    while i<arg[1]:
        yday += ml[i-1]
        i += 1
    yday += arg[2]
    return yday