def calc_adjust(birthdate):
    """
    Calculates the week of the year in which the birthdate occurs (max and min)
    """
    max = 0
    min = 53
    for i in range(7):
        birth_week = (int(birthdate.strftime('%U'))) 
        if birth_week > max:
            max = birth_week
        if birth_week < min:
            min = birth_week
    
    return max, min