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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def dateint_week_by_dateint(dateint, first_day='Monday'):
 """Return a dateint range of the week the given dateint belongs to. Arguments --------- dateint : int An integer object decipting a specific calendaric day; e.g. 20161225. first_day : str, default 'Monday' The first day of the week. Returns ------- iterable An iterable of dateint representing all days of the week the given dateint belongs to. """

    weekday_ix = dateint_to_weekday(dateint, first_day)
    first_day_dateint = shift_dateint(dateint, -weekday_ix)
    last_day_dateint = shift_dateint(first_day_dateint, 6)
    return dateint_range(first_day_dateint, last_day_dateint)