function plt_hide_wpgsi_menus() {
//Hide "Spreadsheet Integrations".
remove_menu_page('wpgsi');
//Hide "Spreadsheet Integrations → Google Spreadsheet Integrations".
remove_submenu_page('wpgsi', 'wpgsi');
//Hide "Spreadsheet Integrations → Show Google Sheet as a table in Post or Page".
remove_submenu_page('wpgsi', 'wpgsi-show');
//Hide "Spreadsheet Integrations → Settings".
remove_submenu_page('wpgsi', 'wpgsi-settings');
//Hide "Spreadsheet Integrations → Contact Us".
remove_submenu_page('wpgsi', 'wpgsi-contact');
//Hide "Spreadsheet Integrations → Upgrade".
remove_submenu_page('wpgsi', 'wpgsi-pricing');
}
add_action('admin_menu', 'plt_hide_wpgsi_menus', 1000000000);