code: @Override
      public DescribeParameterGroupsResult describeParameterGroups(DescribeParameterGroupsRequest request) {
          request = beforeClientExecution(request);
          return executeDescribeParameterGroups(request);
      }
docs: <p>
  Returns a list of parameter group descriptions. If a parameter group name is specified, the list will contain
  only the descriptions for that group.
  </p>
  
  @param describeParameterGroupsRequest
  @return Result of the DescribeParameterGroups operation returned by the service.
  @throws ParameterGroupNotFoundException
  The specified parameter group does not exist.
  @throws ServiceLinkedRoleNotFoundException
  @throws InvalidParameterValueException
  The value for a parameter is invalid.
  @throws InvalidParameterCombinationException
  Two or more incompatible parameters were specified.
  @sample AmazonDax.DescribeParameterGroups
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/dax-2017-04-19/DescribeParameterGroups" target="_top">AWS
  API Documentation</a>