code: protected void textImpl(String value, boolean replaceText) {
          // Issue 10: null text values cause exceptions on subsequent call to
          // Transformer to render document, so we fail-fast here on bad data.
          if (value == null) {
              throw new IllegalArgumentException("Illegal null text value");
          }
  
          if (replaceText) {
              xmlNode.setTextContent(value);
          } else {
              xmlNode.appendChild(getDocument().createTextNode(value));
          }
      }
docs: Add or replace the text value of an element for this builder node.
  
  @param value
  the text value to set or add to the element.
  @param replaceText
  if True any existing text content of the node is replaced with the
  given text value, if the given value is appended to any existing text.