code: function getCategories(options, callback) {
      if (!options) options = {};
  
      return this._request({
        api: '/reactions',
        endpoint: '/populated',
        method: 'GET',
        query: {
          gfyCount: options.gfyCount || 1,
          count: options.count || null,
          cursor: options.cursor || null,
          locale: options.locale || null
        }
      }, callback);
    }
docs: Retrieve JSON array of reactions/categories.
  
  @param {Object} options
  @param {number} options.gfyCount - number of GIFs to include per category.
  @param {string} options.locale - locale for requested language.
  @param {string} options.cursor - cursor for pagination.
  @param {requestCallback} callback - (optional) callback function to run when the request completes.