serialize: function (response, request) {

    // Remove models with no name

    response.models = response.models.filter(element => element.label);

    let qParams = request.queryParams['theme'];

    if (qParams) {

      response.models = response.models

        .slice(0, response.models.length / Math.pow(2, qParams.length))

        .map(t => {

          t.count = Math.max(Math.floor(t.count / 2), 1);

          return t;

        });

    let total = response.models.length;

    // Alphabetical order

    if (request.queryParams.sort === 'alphabetical') {

      response.models.sort(function (a, b) {

        var aLabel = a.label.toUpperCase();

        var bLabel = b.label.toUpperCase();

        if (aLabel < bLabel) { return -1; }

        if (aLabel > bLabel) { return 1; }

        return 0;

      });

      // Descending order

    } else if (request.queryParams.sort === 'descending') {

      response.models.sort(function (a, b) {

        return b.count - a.count;

      });

    }

    var array = [];

    if (typeof request.queryParams.index !== 'undefined' && typeof request.queryParams.limit !== 'undefined') {

      var begin = parseInt(request.queryParams.index) * parseInt(request.queryParams.limit) || 0;

      var end = begin + parseInt(request.queryParams.limit);

      array = response.models.slice(begin, end);

    } else {

      array = response.models;

    }

    return {

      themes: _(array).map((theme) => { return [theme.id, { count: theme.count, label: theme.label }]; }).object().value(),

      meta: {

        total: total

      }

    };

  }