text: # -*- coding=utf-8 -*-
  # library: jionlp
  # author: dongrixinyu
  # license: Apache License 2.0
  # Email: dongrixinyu.89@163.com
  # github: https://github.com/dongrixinyu/JioNLP
  # description: Preprocessing tool for Chinese NLP
  
  
  def bracket(regular_expression):
      return ''.join([r'(', regular_expression, r')'])
  
  
  def bracket_absence(regular_expression):
      return ''.join([r'(', regular_expression, r')?'])
  
  
  def absence(regular_expression):
      return ''.join([regular_expression, r'?'])
  
  
  def start_end(regular_expression):
      return ''.join([r'^', regular_expression, r'$'])
  
  
  