code: function (identifier, params) {
      var path = this.constructPath(constants.DEVICE_MANIFESTS, identifier);
      return this.Core.GET(path, params);
    }
docs: Get all the device manifests or a particular device manifest identified by the `identifier` parameter
  @param  {String|Integer|undefined} identifier A Robin device manifest identifier
  @param  {Object|undefined}         params     A querystring object
  @return {Function}                            A Promise