code: public MockInternetGateway createInternetGateway() {
  
          MockInternetGateway ret = new MockInternetGateway();
          ret.setInternetGatewayId("InternetGateway-"
                  + UUID.randomUUID().toString().substring(0, INTERNETGATEWAY_ID_POSTFIX_LENGTH));
  
          allMockInternetGateways.put(ret.getInternetGatewayId(), ret);
          return ret;
      }
docs: Create the mock InternetGateway.
  @return mock InternetGateway.