code: public String between(int leftIndex, int rightIndex) {
  		String result = this.target4Sub.substring(reviseL(leftIndex), reviseR(rightIndex));
  		return isResetMode ? result : (this.target4Sub = result);
  	}
docs: Returns a new string that is a substring of delegate string
  
  @param leftIndex
  @param rightIndex
  @return