code: @IntRange(from = 1000, to = 9999)
      static int convertTwoDigitYearToFour(@IntRange(from = 0, to = 99) int inputYear) {
          return convertTwoDigitYearToFour(inputYear, Calendar.getInstance());
      }
docs: Converts a two-digit input year to a four-digit year. As the current calendar year
  approaches a century, we assume small values to mean the next century. For instance, if
  the current year is 2090, and the input value is "18", the user probably means 2118,
  not 2018. However, in 2017, the input "18" probably means 2018. This code should be
  updated before the year 9981.
  
  @param inputYear a two-digit integer, between 0 and 99, inclusive
  @return a four-digit year