Adding canvas into chatter feed.cls

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//Prior 32.0v
String comment = 'Click to vote/demote this idea';
// Create feed item input
ConnectApi.FeedItemInput feedItemInput = new ConnectApi.FeedItemInput();
feedItemInput.body = new ConnectApi.MessageBodyInput();

// Create text segment to hold the message body
List<ConnectApi.MessageSegmentInput> segments = new List<ConnectApi.MessageSegmentInput>();
ConnectApi.TextSegmentInput textSegment = new ConnectApi.TextSegmentInput();
textSegment.text = comment;
segments.add(textSegment);
feedItemInput.body.messageSegments = segments;

// Create the canvas attachment
ConnectApi.CanvasAttachmentInput attachmentInput = new ConnectApi.CanvasAttachmentInput();
attachmentInput.developerName = 'Idea_Vote';
attachmentInput.namespacePrefix = 'lk_main';
attachmentInput.title = 'Vote this idea';
attachmentInput.description = '';
attachmentInput.parameters = '{"id":"087900000008Zli"}';    
attachmentInput.height = '100px';
feedItemInput.attachment = attachmentInput;

//Create FeedItemPost//
ConnectApi.FeedItem feedItem = ConnectApi.ChatterFeeds.postFeedItem(null, 
                                                                    ConnectApi.FeedType.RECORD, 
                                                                    'me', 
                                                                    feedItemInput, 
                                                                    null);

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//API version 32.0 onwards
ConnectApi.FeedItemInput input = new ConnectApi.FeedItemInput();
input.feedElementType = ConnectApi.FeedElementType.FeedItem;
input.subjectId = 'me';


ConnectApi.TextSegmentInput textInput = new ConnectApi.TextSegmentInput();
textInput.text = 'This is a sample text to support canvas app.';

ConnectApi.MessageSegmentInput messageInput = (ConnectApi.MessageSegmentInput)textInput;

ConnectApi.MessageBodyInput body = new ConnectApi.MessageBodyInput();
body.messageSegments = new List<ConnectApi.MessageSegmentInput>{messageInput};

input.body = body;

ConnectApi.CanvasCapabilityInput canvas = new ConnectApi.CanvasCapabilityInput();
canvas.developerName = 'Idea_Vote'; 
canvas.namespacePrefix = 'lk_main';//namespace added
canvas.height = '250px';
canvas.parameters = '{"id":"087900000004iGT"}';
canvas.title = 'A new idea has been added with 33.0';

ConnectApi.FeedElementCapabilitiesInput capability = new ConnectApi.FeedElementCapabilitiesInput();
capability.canvas = canvas;

input.capabilities = capability;

List<ConnectApi.BatchInput> feedElements = new List<ConnectApi.BatchInput>();
ConnectApi.BatchInput element = new ConnectApi.BatchInput((object)input);
feedElements.add(element);

ConnectApi.BatchResult[] results = ConnectApi.ChatterFeeds.postFeedElementBatch('internal', feedElements);