stream-start-token()
document-start-token()
tag-token(value=("!!" . "set"))
block-mapping-start-token()
key-token()
scalar-token(plain=#t, style=#f, value="Mark McGwire")
key-token()
scalar-token(plain=#t, style=#f, value="Sammy Sosa")
key-token()
scalar-token(plain=#t, style=#f, value="Ken Griff")
block-end-token()
stream-end-token()