code: def defaults(features):
      
      assert is_iterable_typed(features, Feature)
      # FIXME: should merge feature and property modules.
      from . import property
  
      result = []
      for f in features:
          if not f.free and not f.optional and f.default:
              result.append(property.Property(f, f.default))
  
      return result
docs: Returns the default property values for the given features.