code: public ApiResponse<ApiSuccessResponse> sendDTMFWithHttpInfo(String id, SendDTMFData sendDTMFData) throws ApiException {
          com.squareup.okhttp.Call call = sendDTMFValidateBeforeCall(id, sendDTMFData, null, null);
          Type localVarReturnType = new TypeToken<ApiSuccessResponse>(){}.getType();
          return apiClient.execute(call, localVarReturnType);
      }
docs: Send digits as DTMF
  Send DTMF digits to the specified call. You can send DTMF digits individually with multiple requests or together with multiple digits in one request.
  @param id The connection ID of the call. (required)
  @param sendDTMFData  (required)
  @return ApiResponse&lt;ApiSuccessResponse&gt;
  @throws ApiException If fail to call the API, e.g. server error or cannot deserialize the response body