Unable to (re)create network alias via cli

[dustinrue]

Describe the bug
Unable to recreate network alias. May also fail to create the alias at all, unable to test.

Steps to Reproduce

wp elasticpress recreate-network-alias
Recreating post network alias...
PHP Fatal error:  Uncaught Error: Call to undefined function get_sites() in /Users/dustin/Sites/index.test/wordpress/wp-content/plugins/elasticpress/includes/utils.php:186
Stack trace:
#0 /Users/dustin/Sites/index.test/wordpress/wp-content/plugins/elasticpress/includes/classes/Command.php(419): ElasticPress\Utils\get_sites()
#1 /Users/dustin/Sites/index.test/wordpress/wp-content/plugins/elasticpress/includes/classes/Command.php(401): ElasticPress\Command->create_network_alias_helper(Object(ElasticPress\Indexable\Post\Post))
#2 [internal function]: ElasticPress\Command->recreate_network_alias(Array, Array)
#3 phar:///usr/local/Cellar/wp-cli/2.2.0/bin/wp/vendor/wp-cli/wp-cli/php/WP_CLI/Dispatcher/CommandFactory.php(98): call_user_func(Array, Array, Array)
#4 [internal function]: WP_CLI\Dispatcher\CommandFactory::WP_CLI\Dispatcher\{closure}(Array, Array)
#5 phar:///usr/local/Cellar/wp-cli/2.2.0/bin/wp/vendor/wp-cli/wp-cli/php/WP_CLI/Dispatcher/Subcommand.php(451): call_user_func(Object(Closure), Array, Array)
#6 phar:///usr/local in /Users/dustin/Sites/index.test/wordpress/wp-content/plugins/elasticpress/includes/utils.php on line 186

Expected behavior
No error

Environment information

• Plugins and version: 3.1.3

Additional context

[felipeelia]

We've made a few changes in that part of the code in the last few months and it is fixed. Thanks, @dustinrue!

ps.: Probably it was already working some time ago but I've tested it with 3.5.5 and I can't reproduce it anymore.