code: public Boolean getIncludeStatus() {
  		if (formula.isTrue()) {
  			return Boolean.TRUE;
  		} else if (formula.isFalse()) {
  			return Boolean.FALSE;
  		}
  		return null;
  	}
docs: Returns a Boolean value indicating the value of the formula expression, or null if
  the formula expression contains undefined features.  The formula is NOT simplified
  prior to returning the result for performance reasons, so some expressions that may
  simplify to TRUE can return a null value.
  
  @return the value of the formula or null.