Cache the results of function nodeorder_can_be_ordered($node)

I have found that function nodeorder_can_be_ordered() calls many times and always do the equal SQL query.
For example, in my site this function adds 20 equal SQL queries for each page load!
We can cache the result by using static variable.
I have change function nodeorder_can_be_ordered() from

 function nodeorder_can_be_ordered($node) {
  $sql = "SELECT v.vid AS vid FROM {vocabulary_node_types} vnt JOIN {vocabulary} v ON vnt.vid = v.vid WHERE vnt.type = '%s' AND v.module = 'nodeorder'";
  $result = db_query($sql, $node->type);
  
  if (db_num_rows($result)) {
    return TRUE;
  }
  
  return FALSE;
} 

to

 function nodeorder_can_be_ordered($node) {
  static $can_ordered=array();
  if(isset($can_ordered[$node->type])) return $can_ordered[$node->type];
  $sql = "SELECT v.vid AS vid FROM {vocabulary_node_types} vnt JOIN {vocabulary} v ON vnt.vid = v.vid WHERE vnt.type = '%s' AND v.module = 'nodeorder'";
  $result = db_query($sql, $node->type);
  
  if (db_num_rows($result)) {
    return $can_ordered[$node->type]=TRUE;
  }
  
  return $can_ordered[$node->type]=FALSE;
} 

This manipulation reduce equal queries from 20 to 1!