+STR
+DOC
+MAP
=VAL :sequence
+SEQ <tag:yaml.org,2002:seq>
=VAL :entry
+SEQ <tag:yaml.org,2002:seq>
=VAL :nested
-SEQ
-SEQ
=VAL :mapping
+MAP <tag:yaml.org,2002:map>
=VAL :foo
=VAL :bar
-MAP
-MAP
-DOC
-STR