_post_format_link() WordPress Function

function _post_format_link( $link, $term, $taxonomy ) {
	global $wp_rewrite;
	if ( 'post_format' !== $taxonomy ) {
		return $link;
	}
	if ( $wp_rewrite->get_extra_permastruct( $taxonomy ) ) {
		return str_replace( "/{$term->slug}", '/' . str_replace( 'post-format-', '', $term->slug ), $link );
	} else {
		$link = remove_query_arg( 'post_format', $link );
		return add_query_arg( 'post_format', str_replace( 'post-format-', '', $term->slug ), $link );
	}
}