[tag=VBN] [lemma=field] [□] □
[tag=VBN] [lemma=field] [□=□] □
[tag=VBN] [lemma=field] [□ & □] □
If the field is empty the " if req contains ( order [ i ] ) " line checks for the field name in the list of required fields and returns an error if a required field is empty . There was a far more important way in which privately owned fields were subject to public use .