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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_image(self):
 """ This function is called after the PRE_LOAD filters have been applied. It applies the AFTER_LOAD filters on the result, then crops the image. """

        try:
            result = yield self._fetch(
                self.context.request.image_url
            )

            if not result.successful:
                if result.loader_error == LoaderResult.ERROR_NOT_FOUND:
                    self._error(404)
                    return
                elif result.loader_error == LoaderResult.ERROR_UPSTREAM:
                    # Return a Bad Gateway status if the error came from upstream
                    self._error(502)
                    return
                elif result.loader_error == LoaderResult.ERROR_TIMEOUT:
                    # Return a Gateway Timeout status if upstream timed out (i.e. 599)
                    self._error(504)
                    return
                elif isinstance(result.loader_error, int):
                    self._error(result.loader_error)
                    return
                elif hasattr(result, 'engine_error') and result.engine_error == EngineResult.COULD_NOT_LOAD_IMAGE:
                    self._error(400)
                    return
                else:
                    self._error(500)
                    return

        except Exception as e:
            msg = '[BaseHandler] get_image failed for url `{url}`. error: `{error}`'.format(
                url=self.context.request.image_url,
                error=e
            )

            self.log_exception(*sys.exc_info())

            if 'cannot identify image file' in e.message:
                logger.warning(msg)
                self._error(400)
            else:
                logger.error(msg)
                self._error(500)
            return

        normalized = result.normalized
        buffer = result.buffer
        engine = result.engine

        req = self.context.request

        if engine is None:
            if buffer is None:
                self._error(504)
                return

            engine = self.context.request.engine
            try:
                engine.load(buffer, self.context.request.extension)
            except Exception:
                self._error(504)
                return

        self.context.transformer = Transformer(self.context)

        def transform():
            self.normalize_crops(normalized, req, engine)

            if req.meta:
                self.context.transformer.engine = \
                    self.context.request.engine = \
                    JSONEngine(engine, req.image_url, req.meta_callback)

            self.context.transformer.transform(self.after_transform)

        self.filters_runner.apply_filters(thumbor.filters.PHASE_AFTER_LOAD, transform)