docs: public com.squareup.okhttp.Call getCharactersCharacterIdContractsContractIdItemsAsync(Integer characterId,
              Integer contractId, String datasource, String ifNoneMatch, String token,
              final ApiCallback<List<CharacterContractsItemsResponse>> callback) throws ApiException {
  
          com.squareup.okhttp.Call call = getCharactersCharacterIdContractsContractIdItemsValidateBeforeCall(characterId,
                  contractId, datasource, ifNoneMatch, token, callback);
          Type localVarReturnType = new TypeToken<List<CharacterContractsItemsResponse>>() {
          }.getType();
          apiClient.executeAsync(call, localVarReturnType, callback);
          return call;
      }