code: @Override
      public CacheSubnetGroup createCacheSubnetGroup(CreateCacheSubnetGroupRequest request) {
          request = beforeClientExecution(request);
          return executeCreateCacheSubnetGroup(request);
      }
docs: <p>
  Creates a new cache subnet group.
  </p>
  <p>
  Use this parameter only when you are creating a cluster in an Amazon Virtual Private Cloud (Amazon VPC).
  </p>
  
  @param createCacheSubnetGroupRequest
  Represents the input of a <code>CreateCacheSubnetGroup</code> operation.
  @return Result of the CreateCacheSubnetGroup operation returned by the service.
  @throws CacheSubnetGroupAlreadyExistsException
  The requested cache subnet group name is already in use by an existing cache subnet group.
  @throws CacheSubnetGroupQuotaExceededException
  The request cannot be processed because it would exceed the allowed number of cache subnet groups.
  @throws CacheSubnetQuotaExceededException
  The request cannot be processed because it would exceed the allowed number of subnets in a cache subnet
  group.
  @throws InvalidSubnetException
  An invalid subnet identifier was specified.
  @sample AmazonElastiCache.CreateCacheSubnetGroup
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/elasticache-2015-02-02/CreateCacheSubnetGroup"
  target="_top">AWS API Documentation</a>