filterTenantConfig_(tenantId, keys, baseConfig = {}) {
    const uiConfig = this.getTenantConfig_(tenantId);
    return util.filterProperties(
        /** @type {!Object} */ (uiConfig), keys, baseConfig);
  }
Filters the tenant configuration object by the provided keys.
@param {string} tenantId The tenant ID or project-level config key.
@param {!Array<string>} keys The array of property keys used to filter the
    properties.
@param {!Object=} baseConfig The optional base config object.
@return {!Object} The copy of the config object for the tenant filtered
    by the keys.
@private