protected function prepare_collection_query_args( $request ) {

		$prepared = parent::prepare_collection_query_args( $request );
		if ( is_wp_error( $prepared ) ) {
			return $prepared;
		}

		// Force the post_type argument, since it's not a user input variable.
		$prepared['post_type'] = $this->post_type;

		$query_args = $this->prepare_items_query( $prepared, $request );

		return $query_args;

	}