i am getting this issue  

namespace Abbyy.CloudSdk.V2.Client.Sample
{
    public class HttpClientRetryPolicyHandler : DelegatingHandler
    {
        private readonly IAsyncPolicy<HttpResponseMessage> _retryPolicy;

        /// <summary>Initializes a new instance of the <see cref="HttpClientRetryPolicyHandler"/> class.</summary>
        public HttpClientRetryPolicyHandler(IAsyncPolicy<HttpResponseMessage> retryPolicy)
        {

------->>>>>> Error Here _retryPolicy = retryPolicy ?? throw new ArgumentNullException(nameof(retryPolicy));
------->>>>>> Error Msg
invalid expression term 'throw'

        }

        /// <inheritdoc />
        protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellation) =>
            _retryPolicy.ExecuteAsync(ct => base.SendAsync(request, ct), cancellation);
    }
}