I am implementing a FakeDataSet class by implementing IDbSet interface. As part of implementing this interface, I have to implement Find method. All my entity classes has an Guid type Id column. I am trying to implement Find method for this FakeDbSet class but having hard time to write it in a generic way. Below is my attempts for writing this method but since it does not know about Id been Guid type, I am getting compilation error on m.Id call. Any ideas on how this could be accomplished?

public class FakeDataSet<T> : IDbSet<T> where T: class, new()  
{  
  //  Other methods for implementing  IDbSet interface
  public T Find(params object[] keyValues)  
  {  
       var keyValue = (Guid)keyValues.FirstOrDefault();
       return this.SingleOrDefault(m => m.Id == keyValue);  // How can I write this
  }
}