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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 julian(mon, day, year):
 """ returns julian day """

    ig = 15 + 31 * (10 + 12 * 1582)
    if year == 0:
        print("Julian no can do")
        return
    if year < 0:
        year = year + 1
    if mon > 2:
        julian_year = year
        julian_month = mon + 1
    else:
        julian_year = year - 1
        julian_month = mon + 13
    j1 = int(365.25 * julian_year)
    j2 = int(30.6001 * julian_month)
    j3 = day + 1720995
    julian_day = j1 + j2 + j3
    if day + 31 * (mon + 12 * year) >= ig:
        jadj = int(0.01 * julian_year)
        julian_day = julian_day + 2 - jadj + int(0.25 * jadj)
    return julian_day