def _get_media_files(cls, packager, media_packages, media_type,
                         extra_files):
        """Return source or output media files for a list of packages.

        This will go through the media files belonging to the provided list
        of packages referenced in a Media class and return the output files
        (if Pipeline is enabled) or the source files (if not enabled).

        Args:
            packager (pipeline.packager.Packager):
                The packager responsible for media compilation for this type
                of package.

            media_packages (list of unicode):
                The list of media packages referenced in Media to compile or
                return.

            extra_files (list of unicode):
                The list of extra files to include in the result. This would
                be the list stored in the Media class's original :py:attr:`css`
                or :py:attr:`js` attributes.

        Returns:
            list:
            The list of media files for the given packages.
        """
        source_files = list(extra_files)

        if (not settings.PIPELINE_ENABLED and
            settings.PIPELINE_COLLECTOR_ENABLED):
            default_collector.collect()

        for media_package in media_packages:
            package = packager.package_for(media_type, media_package)

            if settings.PIPELINE_ENABLED:
                source_files.append(
                    staticfiles_storage.url(package.output_filename))
            else:
                source_files += packager.compile(package.paths)

        return source_files
Return source or output media files for a list of packages.

        This will go through the media files belonging to the provided list
        of packages referenced in a Media class and return the output files
        (if Pipeline is enabled) or the source files (if not enabled).

        Args:
            packager (pipeline.packager.Packager):
                The packager responsible for media compilation for this type
                of package.

            media_packages (list of unicode):
                The list of media packages referenced in Media to compile or
                return.

            extra_files (list of unicode):
                The list of extra files to include in the result. This would
                be the list stored in the Media class's original :py:attr:`css`
                or :py:attr:`js` attributes.

        Returns:
            list:
            The list of media files for the given packages.