text: """Email backend that writes messages to a file."""
  
  import datetime
  import os
  
  from django.conf import settings
  from django.core.exceptions import ImproperlyConfigured
  from django.core.mail.backends.console import (
      EmailBackend as ConsoleEmailBackend,
  )
  from django.utils import six
  
  
  class EmailBackend(ConsoleEmailBackend):
      def __init__(self, *args, **kwargs):
          self._fname = None
          if 'file_path' in kwargs:
              self.file_path = kwargs.pop('file_path')
          else:
              self.file_path = getattr(settings, 'EMAIL_FILE_PATH', None)
          # Make sure self.file_path is a string.
          if not isinstance(self.file_path, six.string_types):
              raise ImproperlyConfigured('Path for saving emails is invalid: %r' % self.file_path)
          self.file_path = os.path.abspath(self.file_path)
          # Make sure that self.file_path is an directory if it exists.
          if os.path.exists(self.file_path) and not os.path.isdir(self.file_path):
              raise ImproperlyConfigured(
                  'Path for saving email messages exists, but is not a directory: %s' % self.file_path
              )
          # Try to create it, if it not exists.
          elif not os.path.exists(self.file_path):
              try:
                  os.makedirs(self.file_path)
              except OSError as err:
                  raise ImproperlyConfigured(
                      'Could not create directory for saving email messages: %s (%s)' % (self.file_path, err)
                  )
          # Make sure that self.file_path is writable.
          if not os.access(self.file_path, os.W_OK):
              raise ImproperlyConfigured('Could not write to directory: %s' % self.file_path)
          # Finally, call super().
          # Since we're using the console-based backend as a base,
          # force the stream to be None, so we don't default to stdout
          kwargs['stream'] = None
          super(EmailBackend, self).__init__(*args, **kwargs)
  
      def write_message(self, message):
          self.stream.write(message.message().as_bytes() + b'\n')
          self.stream.write(b'-' * 79)
          self.stream.write(b'\n')
  
      def _get_filename(self):
          """Return a unique file name."""
          if self._fname is None:
              timestamp = datetime.datetime.now().strftime("%Y%m%d-%H%M%S")
              fname = "%s-%s.log" % (timestamp, abs(id(self)))
              self._fname = os.path.join(self.file_path, fname)
          return self._fname
  
      def open(self):
          if self.stream is None:
              self.stream = open(self._get_filename(), 'ab')
              return True
          return False
  
      def close(self):
          try:
              if self.stream is not None:
                  self.stream.close()
          finally:
              self.stream = None
  