old_contents: DEFAULT_CONFIG = {
      'ipc_sock_path': '/tmp/katana.sock',
      'cleaner_db_path': '/tmp/katana_cleaner.db',
      'clean_batch_size': 100,
      'clean_every': 60,
      'proxy': None,
      'accel_redirect': False,
      'accel_redirect_path': '/resized',
      'chunk_size': 16 * 1024,
      'thumb_max_width': 1920,
      'thumb_max_height': 1080,
      'thumb_max_quality': 90,
      'thumb_default_quality': 75,
      'origin_fetch_timeout': 3,
      'origin_timeout': 1,
      'origin_mapping': {
          'localhost': {'ips': ['127.0.0.1'], 'headers': {'Host': 'localhost'}}
      },
      'resize_url_re': None,
      'resize_origin': '',
      'resize_cache_path_source': '',
      'resize_cache_path_resized': '',
      'proxy_url_re': None,
      'proxy_origin': '',
      'proxy_cache_path': '',
      'cache_force_expires': False,
      'cache_default_expires': 300,
      'external_expires': 600,
      'cache_dir': './data',
      'cache_dir_max_usage': 90,
      'logging': {'version': 1},
      'not_found_as_200': False,
      'not_found_source': './404.jpeg',
  }
  
  import os
  import logging.config
  from copy import deepcopy
  
  def get_config(config_file='katana.conf'):
      config = deepcopy(DEFAULT_CONFIG)
      config_file = os.environ.get('CONFIG_FILE', config_file)
      for config_file in [config_file, '/etc/katana/katana.conf']:
          if os.path.exists(config_file):
              execfile(config_file, {}, config)
              break
  
      logging.config.dictConfig(config['logging'])
  
      return config
  
new_contents: DEFAULT_CONFIG = {
      'ipc_sock_path': '/tmp/katana.sock',
      'cleaner_db_path': '/tmp/katana_cleaner.db',
      'clean_batch_size': 100,
      'clean_every': 60,
      'proxy': None,
      'accel_redirect': False,
      'accel_redirect_path': '/resized',
      'chunk_size': 16 * 1024,
      'thumb_max_width': 1920,
      'thumb_max_height': 1080,
      'thumb_max_quality': 90,
      'thumb_default_quality': 75,
      'origin_fetch_timeout': 3,
      'origin_timeout': 1,
      'origin_mapping': {
          'localhost': {'ips': ['127.0.0.1'], 'headers': {'Host': 'localhost'}}
      },
      'resize_url_re': None,
      'resize_origin': '',
      'resize_cache_path_source': '',
      'resize_cache_path_resized': '',
      'proxy_url_re': None,
      'proxy_origin': '',
      'proxy_cache_path': '',
      'cache_force_expires': False,
      'cache_default_expires': 300,
      'external_expires': 600,
      'cache_dir': './data',
      'cache_dir_max_usage': 90,
      'logging': {'version': 1},
      'not_found_as_200': False,
      'not_found_source': './data/404.jpeg',
  }
  
  import os
  import logging.config
  from copy import deepcopy
  
  def get_config(config_file='katana.conf'):
      config = deepcopy(DEFAULT_CONFIG)
      config_file = os.environ.get('CONFIG_FILE', config_file)
      for config_file in [config_file, '/etc/katana/katana.conf']:
          if os.path.exists(config_file):
              execfile(config_file, {}, config)
              break
  
      logging.config.dictConfig(config['logging'])
  
      return config
  
subject: change default path of 404.jpeg