'The CreateReplicationGroup operation creates a replication
group. A replication group is a collection of cache clusters,
where one of the clusters is a read/write primary and the
other clusters are read-only replicas. Writes to the primary
are automatically propagated to the replicas.
When you create a replication group, you must specify an
existing cache cluster that is in the primary role. When the
replication group has been successfully created, you can add
one or more read replica replicas to it, up to a total of five
read replicas.
:type replication_group_id: string
:param replication_group_id:
The replication group identifier. This parameter is stored as a
lowercase string.
Constraints:
+ Must contain from 1 to 20 alphanumeric characters or hyphens.
+ First character must be a letter.
+ Cannot end with a hyphen or contain two consecutive hyphens.
:type primary_cluster_id: string
:param primary_cluster_id: The identifier of the cache cluster that
will serve as the primary for this replication group. This cache
cluster must already exist and have a status of available .
:type replication_group_description: string
:param replication_group_description: A user-specified description for
the replication group.'

def create_replication_group(self, replication_group_id, primary_cluster_id, replication_group_description):

    params = {'ReplicationGroupId': replication_group_id, 'PrimaryClusterId': primary_cluster_id, 'ReplicationGroupDescription': replication_group_description}
    return self._make_request(action='CreateReplicationGroup', verb='POST', path='/', params=params)
