entityfieldquery execution error I'm learning entityfieldquery api

I wrote a simple module

function demo_menu() {
  $items = array();
  $items['demo'] = array(
    'page callback' =&gt; 'demo_list',
    'access callback' =&gt; TRUE,
    'type' =&gt; MENU_CALLBACK,
  );
  return $items;
}

function demo_list() {
  $query=  new EntityFieldQuery();

  $result = $query-&gt;entityCondition('entity_type ', 'node')
    -&gt;execute();

  print_r($result);
}


I got this error

EntityFieldQueryException: For this query an entity type must be specified. in EntityFieldQuery-&gt;propertyQuery() (line 1195 of C:\openserver\domains\drupal7.localhost\includes\entity.inc).


I read many articles. This is the most simplest query but it is not working.
Just got the error. remove space from "entity_type "  
from this line 
$result = $query->entityCondition('entity_type ', 'node') ->execute();