code: def julian(mon, day, year):
      
      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
docs: returns julian day