anchor.diff:  enum DatePickerMode {
     /// Show a date picker UI for choosing a month and day.
     day,
  +
     /// Show a date picker UI for choosing a year.
     year,
   }
  
positive.code: import 'theme.dart';
  import 'typography.dart';
  
  /// Date picker UI mode for either showing a list of available years or a
  /// monthly calendar.
  ///
  /// Also see:
  ///
  
negative.code: ///
  /// An optional [initialDatePickerMode] argument can be used to display the
  /// date picker initially in the year or month+day picker mode. It defaults
  /// to month+day, and must not be null.
  ///
  /// See also:
  ///
  