_transformResponse(response, headers) {
            var headersGetter = this._headersGetter(headers);
            forEach($http.defaults.transformResponse, (transformFn) => {
                response = transformFn(response, headersGetter);
            });
            return response;
        }
Transforms the server response
@param {*} response
@param {Object} headers
@returns {*}
@private