anchor.diff:  import 'theme.dart';
   import 'typography.dart';
   
  +/// Initial display mode of the date picker dialog.
  +///
   /// Date picker UI mode for either showing a list of available years or a
  -/// monthly calendar.
  +/// monthly calendar initially in the dialog shown by calling [showDatePicker].
   ///
   /// Also see:
   ///
  
positive.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, but must not be null.
  ///
  /// See also:
  ///
  
negative.code: enum DatePickerMode {
    /// Show a date picker UI for choosing a month and day.
    day,
  
    /// Show a date picker UI for choosing a year.
    year,
  }
  