How to Hide the "Block External Request" Admin Menu

function plt_hide_blackswan_block_external_request_menus() {
	//Hide the "Settings → Block External Request" menu.
	remove_submenu_page('options-general.php', 'bswan-ber-settings');
}

add_action('admin_menu', 'plt_hide_blackswan_block_external_request_menus', 11);

Where do I put this code?