code: function _getParent(config) {
    if (config.hasOwnProperty('parent')) {
      if (!isString(config.parent)) return config.parent;
      if (cache.has(config.parent)) return cache.get(config.parent);
    }
  
    return settings.get('parent').parent || settings.get('parent');
  }
docs: Get the parent of the module we are trying to create.  Use the given config object supplied to the constructor.
  
  @private
  @param {Object} config     Constructor config.
  @returns {Module}          The parent.