code: def calendar_date(jd_integer):
      
  
      k = jd_integer + 68569
      n = 4 * k // 146097
  
      k = k - (146097 * n + 3) // 4
      m = 4000 * (k + 1) // 1461001
      k = k - 1461 * m // 4 + 31
      month = 80 * k // 2447
      day = k - 2447 * month // 80
      k = month // 11
  
      month = month + 2 - 12 * k
      year = 100 * (n - 49) + m + k
  
      return year, month, day
docs: Convert Julian Day `jd_integer` into a Gregorian (year, month, day).