anchor.diff:  * [tck-testable]#[methodname]`getKey()` returns the key of the node if it is contained in a [classname]`Map`. Returns `null` otherwise.#
   * [tck-testable]#[methodname]`getKind()` returns the [classname]`ElementKind` corresponding to the actual node type. This can be used in conjunction with the method [methodname]`as()` to narrow the type and access node specific methods#
   * [tck-testable]#[methodname]`as(Class<? extends Node>)` returns the node instance narrowed to the type passed as a parameter or [classname]`ClassCastException` if the type and node don't match.#
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   Nodes are of the following possible types:
   
  
positive.code: 
  [classname]`Path` is an iterable of [classname]`Node` objects. [classname]`Node` offers the following methods:
  
  
  
  * [tck-testable]#[methodname]`getName()` returns the name of the element which the node represents:#
  ** `null` if it is a leaf node which represents an entity / bean. In particular, the node representing the root object.
  ** The property name for a property.
  
negative.code: ** a [classname]`PropertyNode` object is added to [classname]`Path` whose `name` equals the name of the property (field name or Java Bean property name). The [classname]`ElementKind` of the node is [varname]`ElementKind.PROPERTY`.
  ** the property path is considered complete
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  [tck-testable]
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