[tag=DT] [lemma=string] [□=□] □ □
[tag=DT] [lemma=string] [tag=□] □ □
[tag=DT] [lemma=string] [lemma=□] □ □
The String may not contain any extraneous characters ( whitespace , for example ) . The string should not contain any character with the value > 255 ( which can only happen if you're using UTF-8 encoding ) .