+STR
+DOC ---
+MAP <tag:yaml.org,2002:map>
=VAL :a
=VAL :b
-MAP
-DOC
+DOC ---
+SEQ <tag:yaml.org,2002:seq>
=VAL <tag:yaml.org,2002:str> :c
-SEQ
-DOC
+DOC ---
=VAL <tag:yaml.org,2002:str> :d e
-DOC
-STR