WP_Filesystem_Base::wp_themes_dir( string|false $theme = false )

Source

File: wp-admin/includes/class-wp-filesystem-base.php

public function wp_themes_dir( $theme = false ) {
		$theme_root = get_theme_root( $theme );

		// Account for relative theme roots.
		if ( '/themes' === $theme_root || ! is_dir( $theme_root ) ) {
			$theme_root = WP_CONTENT_DIR . $theme_root;
		}

		return $this->find_folder( $theme_root );
	}