def create_cache_subnet_group(CacheSubnetGroupName=None,
    CacheSubnetGroupDescription=None, SubnetIds=None):
    """
    Creates a new cache subnet group.
    Use this parameter only when you are creating a cluster in an Amazon Virtual Private Cloud (Amazon VPC).
    See also: AWS API Documentation
    
    
    :example: response = client.create_cache_subnet_group(
        CacheSubnetGroupName='string',
        CacheSubnetGroupDescription='string',
        SubnetIds=[
            'string',
        ]
    )
    
    
    :type CacheSubnetGroupName: string
    :param CacheSubnetGroupName: [REQUIRED]
            A name for the cache subnet group. This value is stored as a lowercase string.
            Constraints: Must contain no more than 255 alphanumeric characters or hyphens.
            Example: mysubnetgroup
            

    :type CacheSubnetGroupDescription: string
    :param CacheSubnetGroupDescription: [REQUIRED]
            A description for the cache subnet group.
            

    :type SubnetIds: list
    :param SubnetIds: [REQUIRED]
            A list of VPC subnet IDs for the cache subnet group.
            (string) --
            

    :rtype: dict
    :return: {
        'CacheSubnetGroup': {
            'CacheSubnetGroupName': 'string',
            'CacheSubnetGroupDescription': 'string',
            'VpcId': 'string',
            'Subnets': [
                {
                    'SubnetIdentifier': 'string',
                    'SubnetAvailabilityZone': {
                        'Name': 'string'
                    }
                },
            ]
        }
    }
    
    
    :returns: 
    CreateCacheSubnetGroup
    ModifyCacheSubnetGroup
    
    """
    pass
