code: public ViewDocumentRequestBuilder addHighlightExpressions(final String highlightExpression, final String... highlightExpressions) {
          this.highlightExpressions.add(highlightExpression);
          this.highlightExpressions.addAll(Arrays.asList(highlightExpressions));
          return this;
      }
docs: Adds values to the highlight_expression parameter
  
  @param highlightExpression  The first highlight expression
  @param highlightExpressions The remaining highlight expressions
  @return this