'Creates a new Amazon Redshift subnet group. You must provide a
list of one or more subnets in your existing Amazon Virtual
Private Cloud (Amazon VPC) when creating Amazon Redshift
subnet group.
For information about subnet groups, go to `Amazon Redshift
Cluster Subnet Groups`_ in the Amazon Redshift Management
Guide .
:type cluster_subnet_group_name: string
:param cluster_subnet_group_name: The name for the subnet group. Amazon
Redshift stores the value as a lowercase string.
Constraints:
+ Must contain no more than 255 alphanumeric characters or hyphens.
+ Must not be "Default".
+ Must be unique for all subnet groups that are created by your AWS
account.
Example: `examplesubnetgroup`
:type description: string
:param description: A description for the subnet group.
:type subnet_ids: list
:param subnet_ids: An array of VPC subnet IDs. A maximum of 20 subnets
can be modified in a single request.'

def create_cluster_subnet_group(self, cluster_subnet_group_name, description, subnet_ids):

    params = {'ClusterSubnetGroupName': cluster_subnet_group_name, 'Description': description}
    self.build_list_params(params, subnet_ids, 'SubnetIds.member')
    return self._make_request(action='CreateClusterSubnetGroup', verb='POST', path='/', params=params)
