Code highlighting:

  def close(self):
      """
      Closes the connection to the database.
      """
      print('1')
      self.validate_thread_sharing()
      # Don't call validate_no_atomic_block() to avoid making it difficult
      # to get rid of a connection in an invalid state. The next connect()
      # will reset the transaction state anyway.

      if self.closed_in_transaction or self.connection is None:
          print('2')
          return
      try:
          self._close()
      finally:
          print('3')
          if self.in_atomic_block:
              print('4')
              self.closed_in_transaction = True
              self.needs_rollback = True
          else:
              print('5')
              self.connection = None
      self.set_clean()