Just some code that i might want to share.

indention.php

 <?php

 class Foo
 {
    private function test()
   {
       $query['body']['aggs'] = [
           'avg_price_per_month' => [
               'date_histogram' => [
                   'field' => 'metaFields.soldDate',
                   'interval' => 'month',
                   'format' => 'M/d/YYYY'
               ],
               [
                   'aggs' => [
                       'terms' => [ 'field' => 'mlsPtID' ],
                       'aggs' => [
                           'average_price' => [
                               'avg' => [
                                   'field' => 'coreFields.soldPrice'
                               ]
                           ]
                       ]
                   ]
               ]
           ]
       ]
   }
 }