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<b>Warning</b>:  session_start(): Session cannot be started after headers have already been sent in <b>/home/tvrreohg/public_html/manga.php</b> on line <b>13</b><br />
﻿'use strict';

module.exports = function keys() {
  let collection = Object.keys(this.items);

  if (Array.isArray(this.items)) {
    collection = collection.map(Number);
  }

  return new this.constructor(collection);
};