public async Task <IList <int> > CharacterAddAsync(SsoToken token, V2ContactCharacterAdd model)
        {
            StaticMethods.CheckToken(token, CharacterScopes.esi_characters_write_contacts_v1);

            string url = StaticConnectionStrings.CheckTestingUrl(StaticConnectionStrings.ContactsV2CharacterAdd(token.CharacterId, model), _testing);

            string jsonObject = JsonConvert.SerializeObject(model.ContactIds);

            EsiModel esiRaw = await PollyPolicies.WebExceptionRetryWithFallbackAsync.ExecuteAsync(async() => await _webClient.PostAsync(StaticMethods.CreateHeaders(token), url, jsonObject));

            return(JsonConvert.DeserializeObject <IList <int> >(esiRaw.Model));
        }