new_contents: from django.core import signals
  from django.db.utils import (
      DEFAULT_DB_ALIAS, DJANGO_VERSION_PICKLE_KEY, ConnectionHandler,
      ConnectionRouter, DatabaseError, DataError, Error, IntegrityError,
      InterfaceError, InternalError, NotSupportedError, OperationalError,
      ProgrammingError,
  )
  
  __all__ = [
      'backend', 'connection', 'connections', 'router', 'DatabaseError',
      'IntegrityError', 'InternalError', 'ProgrammingError', 'DataError',
      'NotSupportedError', 'Error', 'InterfaceError', 'OperationalError',
      'DEFAULT_DB_ALIAS', 'DJANGO_VERSION_PICKLE_KEY'
  ]
  
  connections = ConnectionHandler()
  
  router = ConnectionRouter()
  
  
  # `connection`, `DatabaseError` and `IntegrityError` are convenient aliases
  # for backend bits.
  
  # DatabaseWrapper.__init__() takes a dictionary, not a settings module, so we
  # manually create the dictionary from the settings, passing only the settings
  # that the database backends care about.
  # We load all these up for backwards compatibility, you should use
  # connections['default'] instead.
  class DefaultConnectionProxy(object):
      """
      Proxy for accessing the default DatabaseWrapper object's attributes. If you
      need to access the DatabaseWrapper object itself, use
      connections[DEFAULT_DB_ALIAS] instead.
      """
      def __getattr__(self, item):
          return getattr(connections[DEFAULT_DB_ALIAS], item)
  
      def __setattr__(self, name, value):
          return setattr(connections[DEFAULT_DB_ALIAS], name, value)
  
      def __delattr__(self, name):
          return delattr(connections[DEFAULT_DB_ALIAS], name)
  
      def __eq__(self, other):
          return connections[DEFAULT_DB_ALIAS] == other
  
      def __ne__(self, other):
          return connections[DEFAULT_DB_ALIAS] != other
  
  connection = DefaultConnectionProxy()
  
  
  # Register an event to reset saved queries when a Django request is started.
  def reset_queries(**kwargs):
      for conn in connections.all():
          conn.queries_log.clear()
  signals.request_started.connect(reset_queries)
  
  
  # Register an event to reset transaction state and close connections past
  # their lifetime.
  def close_old_connections(**kwargs):
      for conn in connections.all():
          conn.close_if_unusable_or_obsolete()
  signals.request_started.connect(close_old_connections)
  signals.request_finished.connect(close_old_connections)
  
subject: Create _init_.py