%YAML 1.1
---
- name: spec-02-25
  tree: |
    +STR
    +DOC ---
    +MAP <tag:yaml.org,2002:set>
    =VAL :Mark McGwire
    =VAL :
    =VAL :Sammy Sosa
    =VAL :
    =VAL :Ken Griff
    =VAL :
    -MAP
    -DOC
    -STR
  yaml: |
    # sets are represented as a
    # mapping where each key is
    # associated with the empty string
    --- !!set
    ? Mark McGwire
    ? Sammy Sosa
    ? Ken Griff