new_contents: """Diffviewer features."""
  
  from __future__ import unicode_literals
  
  from django.utils.translation import ugettext_lazy as _
  from djblets.features import Feature, FeatureLevel
  
  
  class FilterInterdiffsV2Feature(Feature):
      """A feature for the 2.0 version of interdiff filtering.
  
      This enables the interdiff filtering logic being made default in
      Review Board 4.0. Starting in Review Board 3.0.18, this can be enabled
      to beta test the new algorithm.
      """
  
      feature_id = 'diffviewer.filter_interdiffs_v2'
      name = _('Interdiff Filtering v2')
      level = FeatureLevel.EXPERIMENTAL
      summary = _("Support for Review Board 4.0's interdiff filtering logic.")
  
  
  filter_interdiffs_v2_feature = FilterInterdiffsV2Feature()
  
subject: Add the missing features.py for interdiff filtering v2.