code: @Override
      public DescribeReplicationGroupsResult describeReplicationGroups(DescribeReplicationGroupsRequest request) {
          request = beforeClientExecution(request);
          return executeDescribeReplicationGroups(request);
      }
docs: <p>
  Returns information about a particular replication group. If no identifier is specified,
  <code>DescribeReplicationGroups</code> returns information about all replication groups.
  </p>
  <note>
  <p>
  This operation is valid for Redis only.
  </p>
  </note>
  
  @param describeReplicationGroupsRequest
  Represents the input of a <code>DescribeReplicationGroups</code> operation.
  @return Result of the DescribeReplicationGroups operation returned by the service.
  @throws ReplicationGroupNotFoundException
  The specified replication group does not exist.
  @throws InvalidParameterValueException
  The value for a parameter is invalid.
  @throws InvalidParameterCombinationException
  Two or more incompatible parameters were specified.
  @sample AmazonElastiCache.DescribeReplicationGroups
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/elasticache-2015-02-02/DescribeReplicationGroups"
  target="_top">AWS API Documentation</a>