code: @Override
      public CreateGroupCertificateAuthorityResult createGroupCertificateAuthority(CreateGroupCertificateAuthorityRequest request) {
          request = beforeClientExecution(request);
          return executeCreateGroupCertificateAuthority(request);
      }
docs: Creates a CA for the group. If a CA already exists, it will rotate the existing CA.
  
  @param createGroupCertificateAuthorityRequest
  @return Result of the CreateGroupCertificateAuthority operation returned by the service.
  @throws BadRequestException
  invalid request
  @throws InternalServerErrorException
  server error
  @sample AWSGreengrass.CreateGroupCertificateAuthority
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/greengrass-2017-06-07/CreateGroupCertificateAuthority"
  target="_top">AWS API Documentation</a>