gistfile1.php

<?php
class Email {
//...
public function setAttachments(array $files) {
    $this->attachment_list = array();

    foreach($files as $filename => $file) {
        if (is_str($filename)) {
            $this->addAttachment($file, $filename);
        } else {
            $this->addAttachment($file);
        }
    }
    return $this;
  }
//...
}