How to use the analytics.log.events function in analytics

function getFunnelData(startDay, eventFunnel, testGroupFn, levelSlugs, logDB) {
  if (!startDay || !eventFunnel || eventFunnel.length === 0 || !testGroupFn) return {};

  // log('getFunnelData:');
  // log(startDay);
  // log(eventFunnel);

  var startObj = objectIdWithTimestamp(ISODate(startDay + "T00:00:00.000Z"));
  var queryParams = {$and: [{_id: {$gte: startObj}},{"event": {$in: eventFunnel}}]};
  var cursor = (logDB.log || db['analytics.log.events']).find(queryParams);

  log("Fetching events..");
  // Map ordering: level, user, event, day
  var levelUserEventMap = {};
  var levelSessions = [];
  var users = [];
  var eventsCounted = 0;
  while (cursor.hasNext()) {
    var doc = cursor.next();
    var created = doc._id.getTimestamp().toISOString();
    var day = created.substring(0, 10);
    var event = doc.event;
    var properties = doc.properties;
    var user = doc.user.valueOf();
    var level = 'n/a';
    var ls = null;

function getLevelFunnelData(startDay, endDay, eventFunnel) {
  // Copied from insertPerDayAnalytics.js
  if (!startDay || !eventFunnel || eventFunnel.length === 0) return {};

  // var startObj = objectIdWithTimestamp(ISODate(startDay + "T00:00:00.000Z"));
  var startObj = objectIdWithTimestamp(ISODate(dataStartDay + "T00:00:00.000Z"));
  var endObj = objectIdWithTimestamp(ISODate(endDay + "T00:00:00.000Z"));
  var queryParams = {$and: [{_id: {$gte: startObj}},{_id: {$lt: endObj}},{"event": {$in: eventFunnel}}]};
  // var queryParams = {$and: [{user: ObjectId("539c630f30a67c3b05d98d95")},{_id: {$gte: startObj}},{_id: {$lt: endObj}},{"event": {$in: eventFunnel}}]};
  var cursor = db['analytics.log.events'].find(queryParams);

  // Map ordering: level, user, event, day
  var recordCount = 0;
  var duplicates = {};
  var levelEventUserDayMap = {};
  var levelUserEventDayMap = {};
  while (cursor.hasNext()) {
    recordCount++;
    var doc = cursor.next();
    var created = doc._id.getTimestamp().toISOString();
    var day = created.substring(0, 10);
    var event = doc.event;
    var properties = doc.properties;
    var user = doc.user;
    var level;

print("Start date is " + startDate)
// var endDate = "2015-01-06T00:00:00.000Z";
// print("End date is " + endDate)

function objectIdWithTimestamp(timestamp)
{
  // Convert string date to Date object (otherwise assume timestamp is a date)
  if (typeof(timestamp) == 'string') timestamp = new Date(timestamp);
  // Convert date object to hex seconds since Unix epoch
  var hexSeconds = Math.floor(timestamp/1000).toString(16);
  // Create an ObjectId with that hex timestamp
  var constructedObjectId = ObjectId(hexSeconds + "0000000000000000");
  return constructedObjectId
}

var cursor = db['analytics.log.events'].find({
  $and: [
    {_id: {$gte: objectIdWithTimestamp(ISODate(startDate))}},
    {$or: [ {"event" : 'Started Level'}, {"event" : 'Saw Victory'}]}
    ]
});

var longestLevelName = -1;


// Copied from WorldMapView
var dungeonLevels = [
  'dungeons-of-kithgard',
  'gems-in-the-deep',
  'shadow-guard',
  'kounter-kithwise',
  'crawlways-of-kithgard',

}
    }
};
var group={"$group" : {
        "_id" : {
            "m" : "$event",
            "d" : "$created"
        },
        "count" : {
            "$sum" : 1
        }
    }
};
var conversionsPerDay = {};
var sort = {$sort: { "_id.d" : -1}};
var cursor = db['analytics.log.events'].aggregate(match, proj1, proj2, group, sort);

while (cursor.hasNext()) {
  var myDoc = cursor.next();
  var key = myDoc._id.d.toDateString()
  if (!conversionsPerDay[key]) conversionsPerDay[key] = {}
  conversionsPerDay[key][myDoc._id.m] = myDoc.count;
}
for (key in conversionsPerDay) {
    print(key + "\t" + conversionsPerDay[key]['Started Signup'] + "\t" + conversionsPerDay[key]['Finished Signup'] + "\t" + (conversionsPerDay[key]['Finished Signup'] / conversionsPerDay[key]['Started Signup'] * 100).toFixed(2) + "%");
}