code: public Span[] seqToSpans(final String[] tokens) {
      final Span[] origSpans = this.sequenceLabeler.tag(tokens);
      final Span[] seqSpans = SequenceLabelerME.dropOverlappingSpans(origSpans);
      return seqSpans;
    }
docs: Tag the current sentence.
  
  @param tokens
  the current sentence
  @return the array of span sequences