old_contents: from con.base_dict import DictionaryInterface
  import sqlite3
  
  class Dictionary(DictionaryInterface):
      """
      字典，作为整个程序的model部分
      """
  
      def __init__(self):
          self.SEARCH_A_WORD = \
                  'SELECT meanings, examples FROM words WHERE word=?'
  
          self.__conn = sqlite3.connect('./dict.db')
  
      def get_meaning(self, word):
          """
          获取单词释义
          :word:      单词，str类型，不保证输入安全
          :return:    返回单词的解释和例句
          """
          word = (word.strip().lower(), )
          c = self.__conn.cursor()
          result = c.execute(self.SEARCH_A_WORD, word).fetchone()
          if result is None:
              result = ('', '')
          return result
  
new_contents: from con.base_dict import DictionaryInterface
  import sqlite3
  
  class Dictionary(DictionaryInterface):
      """
      字典，作为整个程序的model部分
      """
  
      def __init__(self):
          self.SEARCH_A_WORD = \
                  'SELECT meanings, examples FROM words WHERE word=?'
  
          self.__conn = sqlite3.connect('./dict.db')
  
      def __def__(self):
          self.__conn.close()
  
      def get_meaning(self, word):
          """
          获取单词释义
          :word:      单词，str类型，不保证输入安全
          :return:    返回单词的解释和例句
          """
          word = (word.strip().lower(), )
          c = self.__conn.cursor()
          result = c.execute(self.SEARCH_A_WORD, word).fetchone()
          if result is None:
              result = ('', '')
          return result
  
subject: fix sql connector doesn't close bug