def create_snapshot(ReplicationGroupId=None, CacheClusterId=None,
    SnapshotName=None):
    """
    Creates a copy of an entire cache cluster or replication group at a specific moment in time.
    See also: AWS API Documentation
    
    
    :example: response = client.create_snapshot(
        ReplicationGroupId='string',
        CacheClusterId='string',
        SnapshotName='string'
    )
    
    
    :type ReplicationGroupId: string
    :param ReplicationGroupId: The identifier of an existing replication group. The snapshot is created from this replication group.

    :type CacheClusterId: string
    :param CacheClusterId: The identifier of an existing cache cluster. The snapshot is created from this cache cluster.

    :type SnapshotName: string
    :param SnapshotName: [REQUIRED]
            A name for the snapshot being created.
            

    :rtype: dict
    :return: {
        'Snapshot': {
            'SnapshotName': 'string',
            'ReplicationGroupId': 'string',
            'ReplicationGroupDescription': 'string',
            'CacheClusterId': 'string',
            'SnapshotStatus': 'string',
            'SnapshotSource': 'string',
            'CacheNodeType': 'string',
            'Engine': 'string',
            'EngineVersion': 'string',
            'NumCacheNodes': 123,
            'PreferredAvailabilityZone': 'string',
            'CacheClusterCreateTime': datetime(2015, 1, 1),
            'PreferredMaintenanceWindow': 'string',
            'TopicArn': 'string',
            'Port': 123,
            'CacheParameterGroupName': 'string',
            'CacheSubnetGroupName': 'string',
            'VpcId': 'string',
            'AutoMinorVersionUpgrade': True|False,
            'SnapshotRetentionLimit': 123,
            'SnapshotWindow': 'string',
            'NumNodeGroups': 123,
            'AutomaticFailover': 'enabled'|'disabled'|'enabling'|'disabling',
            'NodeSnapshots': [
                {
                    'CacheClusterId': 'string',
                    'NodeGroupId': 'string',
                    'CacheNodeId': 'string',
                    'NodeGroupConfiguration': {
                        'Slots': 'string',
                        'ReplicaCount': 123,
                        'PrimaryAvailabilityZone': 'string',
                        'ReplicaAvailabilityZones': [
                            'string',
                        ]
                    },
                    'CacheSize': 'string',
                    'CacheNodeCreateTime': datetime(2015, 1, 1),
                    'SnapshotCreateTime': datetime(2015, 1, 1)
                },
            ]
        }
    }
    
    
    :returns: 
    General purpose:
    Current generation: cache.t2.micro , cache.t2.small , cache.t2.medium , cache.m3.medium , cache.m3.large , cache.m3.xlarge , cache.m3.2xlarge , cache.m4.large , cache.m4.xlarge , cache.m4.2xlarge , cache.m4.4xlarge , cache.m4.10xlarge
    Previous generation: cache.t1.micro , cache.m1.small , cache.m1.medium , cache.m1.large , cache.m1.xlarge
    
    
    Compute optimized: cache.c1.xlarge
    Memory optimized:
    Current generation: cache.r3.large , cache.r3.xlarge , cache.r3.2xlarge , cache.r3.4xlarge , cache.r3.8xlarge
    Previous generation: cache.m2.xlarge , cache.m2.2xlarge , cache.m2.4xlarge
    
    
    
    """
    pass
