public bool Contains(Milestone value)
 {
     // If value is not of type Milestone, this will return false.
     return(List.Contains(value));
 }
 public void Remove(Milestone value)
 {
     List.Remove(value);
 }
 public int IndexOf(Milestone value)
 {
     return(List.IndexOf(value));
 }
 public void Insert(int index, Milestone value)
 {
     List.Insert(index, value);
 }
 public int Add(Milestone value)
 {
     return(List.Add(value));
 }