public static function underscorize($word) {
    $word = preg_replace('/[\'"]/', '', $word);
    $word = preg_replace('/[^a-zA-Z0-9]+/', '_', $word);
    $word = preg_replace('/([A-Z\d]+)([A-Z][a-z])/', '\1_\2', $word);
    $word = preg_replace('/([a-z\d])([A-Z])/', '\1_\2', $word);
    $word = trim($word, '_');
    $word = strtolower($word);
    $word = str_replace('boleto_simples_', '', $word);
    return $word;
  }