def get_thumbnail(self, file_, geometry_string, **options):
        """
        Returns thumbnail as an ImageFile instance for file with geometry and
        options given. First it will try to get it from the key value store,
        secondly it will create it.
        """
        logger.debug(text_type('Getting thumbnail for file [%s] at [%s]'), file_, geometry_string)

        if file_:
            source = ImageFile(file_)
        elif settings.THUMBNAIL_DUMMY:
            return DummyImageFile(geometry_string)
        else:
            return None

        # preserve image filetype
        if settings.THUMBNAIL_PRESERVE_FORMAT:
            options.setdefault('format', self._get_format(source))

        for key, value in self.default_options.items():
            options.setdefault(key, value)

        # For the future I think it is better to add options only if they
        # differ from the default settings as below. This will ensure the same
        # filenames being generated for new options at default.
        for key, attr in self.extra_options:
            value = getattr(settings, attr)
            if value != getattr(default_settings, attr):
                options.setdefault(key, value)

        name = self._get_thumbnail_filename(source, geometry_string, options)
        thumbnail = ImageFile(name, default.storage)
        cached = default.kvstore.get(thumbnail)

        if cached:
            return cached

        # We have to check exists() because the Storage backend does not
        # overwrite in some implementations.
        if settings.THUMBNAIL_FORCE_OVERWRITE or not thumbnail.exists():
            try:
                source_image = default.engine.get_image(source)
            except __HOLE__ as e:
                logger.exception(e)
                if settings.THUMBNAIL_DUMMY:
                    return DummyImageFile(geometry_string)
                else:
                    # if S3Storage says file doesn't exist remotely, don't try to
                    # create it and exit early.
                    # Will return working empty image type; 404'd image
                    logger.warn(text_type('Remote file [%s] at [%s] does not exist'),
                                file_, geometry_string)

                    return thumbnail

            # We might as well set the size since we have the image in memory
            image_info = default.engine.get_image_info(source_image)
            options['image_info'] = image_info
            size = default.engine.get_image_size(source_image)
            source.set_size(size)

            try:
                self._create_thumbnail(source_image, geometry_string, options,
                                       thumbnail)
                self._create_alternative_resolutions(source_image, geometry_string,
                                                     options, thumbnail.name)
            finally:
                default.engine.cleanup(source_image)

        # If the thumbnail exists we don't create it, the other option is
        # to delete and write but this could lead to race conditions so I
        # will just leave that out for now.
        default.kvstore.get_or_set(source)
        default.kvstore.set(thumbnail, source)
        return thumbnail
dataset/ETHPy150Open mariocesar/sorl-thumbnail/sorl/thumbnail/base.py/ThumbnailBackend.get_thumbnail