old_contents: import re
  
  class BaseExtractor(object):
      regex = None
  
      def _extract(self, html, regex=None):
          result =[]
          if regex == None:
              regex = self.regex
  
          if regex == None:
              return result
  
          p = re.compile(regex)
  
          result = p.findall(html)
          return result
  
      def extract(self, html, regex=None):
          return self._extract(html, regex=regex)
  
new_contents: import re
  
  class BaseExtractor(object):
  
      def _extract(self, html):
          result =[]
          return result
  
      def extract(self, html):
          return self._extract(html)
  
  class BaseRegexExtractor(object):
      regex = None
  
      def _extract(self, html, regex=None):
          result =[]
          if regex == None:
              regex = self.regex
  
          if regex == None:
              return result
  
          p = re.compile(regex)
  
          result = p.findall(html)
          return result
  
      def extract(self, html, regex=None):
          return self._extract(html, regex=regex)
  
subject: add class BaseRegexExtractor