Untraversable (Jython API documentation)
Date: 2022-09-10

org.python.core

## Annotation Type Untraversable

-     @Retention(value=RUNTIME)
       @Target(value=TYPE)
      public @interface Untraversable

  Indicates that a given class is not traversable and does intentionally not implement `Traverseproc`. This annotation is ignored if the class implements `Traverseproc`, i.e. it cannot be used to remove `Traverseproc` support of a superclass. Thus it is well defined what happens if both `Traverseproc` and `{@literal @}Untraversable` are present: `Traverseproc` wins.
  If a class does not implement `Traverseproc` and is not annotated with `{@literal @}Untraversable`, gc assumes that the programmers were not aware of Jython's traverse mechanism and attempts to traverse the target object by using Java-reflection (which is assumably very inefficient).

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