public Range<C> until(C to){
  Objects.requireNonNull(to);
  this.to=to;
  toIncluded=false;
  return this;
}

public Range < C > until ( C to ) { Objects . requireNonNull ( to ) ; this . to = to ; toIncluded = false ; return this ; }
set end point . the end point is excluded in this range .
