Adding template suggestions for page by node types in Drupal 8

mytheme.theme.php

<?php
/**
 * Implementation of hook_theme_suggestions_HOOK_alter() for page.html.twig.
 */
function MYTHEME_theme_suggestions_page_alter(array &$suggestions, array $variables) {
  // Add template suggestions based on the current node entity content type.
  $key = array_search('page__node', $suggestions);
  if ($key !== FALSE && ($node = \Drupal::routeMatch()->getParameter('node'))) {
    $content_type = $node->bundle();
    array_splice($suggestions, ++$key, 0, array('page__node_type__%', 'page__node_type__'.$content_type));
  }
}