code: public ListInstanceSpecsResponse listInstanceSpecs(ListInstanceSpecsRequest request) {
          InternalRequest internalRequest = this.createRequest(
                  request, HttpMethodName.GET, INSTANCE_PREFIX, "spec");
          return this.invokeHttpClient(internalRequest, ListInstanceSpecsResponse.class);
      }
docs: The interface will be deprecated in the future,
  we suggest to use triad (instanceType，cpuCount，memoryCapacityInGB) to specified the instance configuration.
  
  Listing all of specification for instance resource to buy.
  
  See more detail on
  <a href = "https://bce.baidu.com/doc/BCC/API.html#.E5.AE.9E.E4.BE.8B.E5.A5.97.E9.A4.90.E8.A7.84.E6.A0.BC">
  BCE API doc</a>
  
  @param request The request containing all options for Listing all of specification for instance resource.
  @return List of specification for instance resource to buy.