public async Task <TalksByUser> GetTalksBySpeaker(string speakerName)
{
var talks = await conferencePersistence.GetTalksFromConferences(conferenceIds);
var orderedTalks = talks.Where(t => t.Speaker.Contains(speakerName)).OrderByDescending(t => t.DateOfTalk);
var orderedSummaries = (await CreateTalkSummaries(orderedTalks)).ToArray();
var user = users.GetUser(speakerName);
var slackDmLink = slackClient.GetDmLink(user.Name, user.SlackId);
var talksByUser = new TalksByUser(user, orderedSummaries, slackDmLink);
return(talksByUser);
}