Fixed minor bugs

src/Language/AST/Node.php

@@ -60,7 +60,7 @@ abstract class Node
      * This is a reverse operation for $node->toArray(true)
      *
      * @param array $node
-     * @return EnumValueDefinitionNode
+     * @return Node
      */
     public static function fromArray(array $node)
     {

src/Server/StandardServer.php

@@ -72,7 +72,7 @@ class StandardServer
      */
     public function executeRequest($parsedBody = null)
     {
-        if (null !== $parsedBody) {
+        if (null === $parsedBody) {
             $parsedBody = $this->helper->parseHttpRequest();
         }