public bool Delete(Speaker t)
        {
            var speaker = SpeakerInMemory.GetInstance().Speakers.FirstOrDefault(s => s.Id == t.Id);

            if (speaker == null)
            {
                return(false);
            }

            speaker.Deleted = true;
            return(true);
        }
        public Speaker Update(Speaker t)
        {
            var speaker = SpeakerInMemory.GetInstance().Speakers.FirstOrDefault(s => s.Id == t.Id);

            if (speaker == null)
            {
                return(null);
            }
            speaker.Birthday = t.Birthday;
            speaker.Deleted  = t.Deleted;
            speaker.Name     = t.Name;
            speaker.Sessions = t.Sessions;
            return(speaker);
        }
 public Speaker Create(Speaker t)
 {
     t.Id = new Guid();
     SpeakerInMemory.GetInstance().Speakers.Append(t);
     return(t);
 }
 public ICollection <Speaker> FindAllSpeakers()
 {
     return((ICollection <Speaker>)SpeakerInMemory.GetInstance().Speakers);
 }