code: public boolean encloses(Span other) {
        return other != null && other.start() >= this.start() && other.end() < this.end();
     }
docs: Returns true if the bounds of the other text do not extend outside the bounds of this text.
  
  @param other The other text to check if this one encloses
  @return True if the two texts are in the same document and this text encloses the other, False otherwise