anchor.diff:  
   	_renderSection(node) {
   		final value = _resolveValue(node.value);
  -		if (value is List) {
  +		if (value == null) {
  +			// Do nothing.
  +		} else if (value is Iterable) {
   			value.forEach((v) => _renderSectionWithValue(node, v));
   		} else if (value is Map) {
   			_renderSectionWithValue(node, value);
  
positive.code: 
  	_renderInvSection(node) {
  		final value = _resolveValue(node.value);
  		if ((value is List && value.isEmpty) || value == false) {
  			_renderSectionWithValue(node, value);
  		} else if (value == true || value is Map || value is List) {
  			// Do nothing.
  		} else if (value == null) {
  			if (_lenient) {
  				_renderSectionWithValue(node, value);
  			} else {
  				throw new MustacheFormatException(
  					'Value was null or missing, '
  					'inverse-section: ${node.value}, '
  					'at: ${node.line}:${node.column}.', node.line, node.column);
  			}
  
negative.code: 		_sink = sink;
  		_htmlEscapeValues = htmlEscapeValues;
  		_stack.clear();
  		_stack.add(values);
  		_root.children.forEach(_renderNode);
  		_sink = null;
  	}
  