public static async Task <HttpResponseMessage> AccountSendersChangeEmailAsync(IEnumerable <string> emails)
 {
     using (var client = new eSign20HttpClient())
         return(await client.PostAsJsonAsync <dynamic>("api/v1/account/senders/group/", new { emails = emails }));
 }
 internal static async Task <HttpResponseMessage> AccountSendersAsync(string email, CancellationToken cancellationToken)
 {
     using (var client = new eSign20HttpClient())
         return(await client.PostAsJsonAsync <dynamic>("api/v1/account/senders/", new { email = email }, cancellationToken));
 }