anchor.diff:    /// Returns the point in time that's given amount of time ago. The
     /// amount of time is the sum of individual parts. Parts are compatible with
     /// ones defined in [Duration].
  -  DateTime ago({int days: 0, int hours: 0, int minutes: 0, int seconds: 0,
  -      int milliseconds: 0, int microseconds: 0}) => agoBy(new Duration(
  +  DateTime ago(
  +          {int days: 0,
  +          int hours: 0,
  +          int minutes: 0,
  +          int seconds: 0,
  +          int milliseconds: 0,
  +          int microseconds: 0}) =>
  +      agoBy(new Duration(
             days: days,
             hours: hours,
             minutes: minutes,
  
positive.code: 
  /// Days in a month. This array uses 1-based month numbers, i.e. January is
  /// the 1-st element in the array, not the 0-th.
  const _DAYS_IN_MONTH =
      const [ 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 ];
  
  int _daysInMonth(int year, int month) => (month == DateTime.FEBRUARY &&
      _isLeapYear(year)) ? 29 : _DAYS_IN_MONTH[month];
  
  bool _isLeapYear(int year) =>
      (year % 4 == 0) && ((year % 100 != 0) || (year % 400 == 0));
  
negative.code:   /// Returns the point in time that's given amount of time from now. The
    /// amount of time is the sum of individual parts. Parts are compatible with
    /// ones defined in [Duration].
    DateTime fromNow(
            {int days: 0,
            int hours: 0,
            int minutes: 0,
            int seconds: 0,
            int milliseconds: 0,
            int microseconds: 0}) =>
        fromNowBy(new Duration(
            days: days,
            hours: hours,
            minutes: minutes,
  