Fix code style.

Author: drupol

src/Exporter/Ascii.php

@@ -57,8 +57,7 @@ public function export(NodeInterface $node): string
      */
     private function doExportAsArray(NodeInterface $node): array
     {
-        if (!($node instanceof ValueNodeInterface))
-        {
+        if (!($node instanceof ValueNodeInterface)) {
             throw new \InvalidArgumentException('Must implements ValueNodeInterface');
         }
 

src/Exporter/Graph.php

@@ -5,7 +5,6 @@
 namespace drupol\phptree\Exporter;
 
 use drupol\phptree\Node\NodeInterface;
-use drupol\phptree\Node\ValueNodeInterface;
 use drupol\phptree\Traverser\BreadthFirst;
 use drupol\phptree\Traverser\TraverserInterface;
 use Fhaculty\Graph\Graph as OriginalGraph;
@@ -98,8 +97,8 @@ protected function createVertex(NodeInterface $node): Vertex
         if (false === $this->getGraph()->hasVertex($vertexId)) {
             $vertex = $this->getGraph()->createVertex($vertexId);
 
-            $label = NULL;
-            if (method_exists($node, 'getValue')) {
+            $label = null;
+            if (\method_exists($node, 'getValue')) {
                 $label = $node->getValue();
             }
 

src/Exporter/SimpleArray.php

@@ -17,8 +17,7 @@ class SimpleArray implements ExporterInterface
      */
     public function export(NodeInterface $node)
     {
-        if (!($node instanceof ValueNodeInterface))
-        {
+        if (!($node instanceof ValueNodeInterface)) {
             throw new \InvalidArgumentException('Must implements ValueNodeInterface');
         }
 

src/Exporter/Text.php

@@ -17,8 +17,7 @@ class Text implements ExporterInterface
      */
     public function export(NodeInterface $node): string
     {
-        if (!($node instanceof ValueNodeInterface))
-        {
+        if (!($node instanceof ValueNodeInterface)) {
             throw new \InvalidArgumentException('Must implements ValueNodeInterface');
         }