PhpParser\PrettyPrinterAbstract::prettyPrintFile PHP Method

    public function prettyPrintFile(array $stmts)
    {
        if (!$stmts) {
            return "<?php\n\n";
        }
        $p = "<?php\n\n" . $this->prettyPrint($stmts);
        if ($stmts[0] instanceof Stmt\InlineHTML) {
            $p = preg_replace('/^<\\?php\\s+\\?>\\n?/', '', $p);
        }
        if ($stmts[count($stmts) - 1] instanceof Stmt\InlineHTML) {
            $p = preg_replace('/<\\?php$/', '', rtrim($p));
        }
        return $p;
    }

 /**
  * {@inheritdoc}
  */
 public function write(array $fileNodes)
 {
     $result = [];
     foreach ($fileNodes as $fileName => $nodes) {
         $result[$fileName] = $this->printer->prettyPrintFile($nodes);
     }
     return $result;
 }