ansible-vault encrypt_string and inventory files

Have you tried

     ansible_password: !vault |
       $ANSIBLE_VAULT;1.1;AES256
       30653431356634633165316664383264313636623136623831663566303436613834366536663333
       6236666435613164306162346261666339353230356365360a383661333263656465646533386561
       33393937323838646264396166333266633062633330386630643161343365313533306135663332
       6438373531326334310a316232386532313563363531303833373964363130633735636631396364
       6662

because I think the string should come right after the colon and no grater than sign.