anchor.diff:          return completer.future;
   
         }, onError: (e) {
  -        _nonFastForward();
  +        _nonFastForwardPush();
         });
       }
       return getNextCommit(sha);
  
positive.code:           return _getCommits(remoteRef, remoteShas, sha);
  
          }, onError: (e) {
            // no commits to push.
            throw "no commits to push.";
          });
        });
      });
  
negative.code: 
  import 'config.dart';
  import 'constants.dart';
  import 'exception.dart';
  import 'fast_sha.dart';
  import 'file_operations.dart';
  import 'commands/index.dart';
  