code: public void marshall(GetUsagePlanKeysRequest getUsagePlanKeysRequest, ProtocolMarshaller protocolMarshaller) {
  
          if (getUsagePlanKeysRequest == null) {
              throw new SdkClientException("Invalid argument passed to marshall(...)");
          }
  
          try {
              protocolMarshaller.marshall(getUsagePlanKeysRequest.getUsagePlanId(), USAGEPLANID_BINDING);
              protocolMarshaller.marshall(getUsagePlanKeysRequest.getPosition(), POSITION_BINDING);
              protocolMarshaller.marshall(getUsagePlanKeysRequest.getLimit(), LIMIT_BINDING);
              protocolMarshaller.marshall(getUsagePlanKeysRequest.getNameQuery(), NAMEQUERY_BINDING);
          } catch (Exception e) {
              throw new SdkClientException("Unable to marshall request to JSON: " + e.getMessage(), e);
          }
      }
docs: Marshall the given parameter object.