/// <summary>
        /// Sets the URL of the event.
        /// </summary>
        /// <param name="url">
        /// URL, must not be empty.
        /// </param>
        /// <returns>
        /// A reference to the modified builder.
        /// </returns>
        /// <exception cref="ArgumentException">
        /// Thrown if <paramref name="url"/> is empty.
        /// </exception>
        public UpsertEventRequestBuilder Url(string url)
        {
            this.url = new NullableString(url);

            return(this);
        }
        /// <summary>
        /// Sets the URL of the event.
        /// </summary>
        /// <param name="url">
        /// URL, must not be empty.
        /// </param>
        /// <returns>
        /// A reference to the modified builder.
        /// </returns>
        /// <exception cref="ArgumentException">
        /// Thrown if <paramref name="url"/> is empty.
        /// </exception>
        public SmartInviteEventRequestBuilder Url(string url)
        {
            this.url = new NullableString(url);

            return(this);
        }