private void TakeOff(int from)
{
bool owlWasPresent = PositionsWithOwls.Remove(from);
if (!owlWasPresent)
{
throw new InvalidMoveException("There is no owl at position " + from);
}
}
public void Move(int from, int to)
{
TakeOff(from);
PositionsWithOwls.Add(to);
}
public bool Inhabit(int position)
{
return(PositionsWithOwls.Contains(position));
}
