'The CreateCacheSubnetGroup operation creates a new cache
subnet group.
Use this parameter only when you are creating a cluster in an
Amazon Virtual Private Cloud (VPC).
:type cache_subnet_group_name: string
:param cache_subnet_group_name: 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 cache_subnet_group_description: string
:param cache_subnet_group_description: A description for the cache
subnet group.
:type subnet_ids: list
:param subnet_ids: A list of VPC subnet IDs for the cache subnet group.'

def create_cache_subnet_group(self, cache_subnet_group_name, cache_subnet_group_description, subnet_ids):

    params = {'CacheSubnetGroupName': cache_subnet_group_name, 'CacheSubnetGroupDescription': cache_subnet_group_description}
    self.build_list_params(params, subnet_ids, 'SubnetIds.member')
    return self._make_request(action='CreateCacheSubnetGroup', verb='POST', path='/', params=params)
