old_contents: import importlib
  
  parsers = """
  singtao.STParser
  apple.AppleParser
  """.split()
  
  parser_dict = {}
  
  # Import the parser and fill in parser_dict: domain -> parser
  for parser_name in parsers:
      module, class_name = parser_name.rsplit('.', 1)
      parser = getattr(importlib.import_module('parsers.' + module), class_name)
      for domain in parser.domains:
          parser_dict[domain] = parser
  
  
  def get_parser(url):
      return parser_dict[url.split('/')[2]]
  
  # Each feeder places URLs into the database to be checked periodically.
  parsers = [parser for parser in parser_dict.values()]
  
  __all__ = ['parsers', 'get_parser']
new_contents: import importlib
  
  parsers = """
  singtao.STParser
  apple.AppleParser
  tvb.TVBParser
  """.split()
  
  parser_dict = {}
  
  # Import the parser and fill in parser_dict: domain -> parser
  for parser_name in parsers:
      module, class_name = parser_name.rsplit('.', 1)
      parser = getattr(importlib.import_module('parsers.' + module), class_name)
      for domain in parser.domains:
          parser_dict[domain] = parser
  
  
  def get_parser(url):
      return parser_dict[url.split('/')[2]]
  
  # Each feeder places URLs into the database to be checked periodically.
  parsers = [parser for parser in parser_dict.values()]
  
  __all__ = ['parsers', 'get_parser']
subject: Add tvb Parser to the init