anchor.diff:  /// [Project]s in the group simultaneously
   CompositeProjectCommand projectCommandGroup(
       String name, Iterable<ProjectCommand> commands,
  -    {CommandConcurrencyMode concurrencyMode: CommandConcurrencyMode.concurrentCommand}) {
  +    {CommandConcurrencyMode concurrencyMode:
  +        CommandConcurrencyMode.concurrentCommand}) {
     return new _DefaultCompositeProjectCommand(name, commands, concurrencyMode);
   }
   
  
positive.code:   ProjectCommandError(this.command, this.project, this.cause);
  
    String toString() => 'ProjectCommandError: $message';
  }
  
  class _DefaultCommand implements ProjectCommand {
  
negative.code: 
  /// A command that operates on a single [Project]
  ProjectCommand projectCommand(String name, ProjectFunction function,
          {CommandConcurrencyMode concurrencyMode:
              CommandConcurrencyMode.concurrentCommand,
          Condition condition: _alwaysYes}) =>
      new _DefaultCommand(name, function, concurrencyMode, condition);
  
  