code: public LocalDateTime minusDays(long days) {
          return (days == Long.MIN_VALUE ? plusDays(Long.MAX_VALUE).plusDays(1) : plusDays(-days));
      }
docs: Returns a copy of this {@code LocalDateTime} with the specified number of days subtracted.
  <p>
  This method subtracts the specified amount from the days field decrementing the
  month and year fields as necessary to ensure the result remains valid.
  The result is only invalid if the maximum/minimum year is exceeded.
  <p>
  For example, 2009-01-01 minus one day would result in 2008-12-31.
  <p>
  This instance is immutable and unaffected by this method call.
  
  @param days  the days to subtract, may be negative
  @return a {@code LocalDateTime} based on this date-time with the days subtracted, not null
  @throws DateTimeException if the result exceeds the supported date range