def update_shard_count(StreamName=None, TargetShardCount=None, ScalingType=None
    ):
    """
    Updates the shard count of the specified stream to the specified number of shards.
    Updating the shard count is an asynchronous operation. Upon receiving the request, Amazon Kinesis returns immediately and sets the status of the stream to UPDATING . After the update is complete, Amazon Kinesis sets the status of the stream back to ACTIVE . Depending on the size of the stream, the scaling action could take a few minutes to complete. You can continue to read and write data to your stream while its status is UPDATING .
    To update the shard count, Amazon Kinesis performs splits and merges and individual shards. This can cause short-lived shards to be created, in addition to the final shards. We recommend that you double or halve the shard count, as this results in the fewest number of splits or merges.
    This operation has a rate limit of twice per rolling 24 hour period. You cannot scale above double your current shard count, scale below half your current shard count, or exceed the shard limits for your account.
    For the default limits for an AWS account, see Streams Limits in the Amazon Kinesis Streams Developer Guide . If you need to increase a limit, contact AWS Support .
    See also: AWS API Documentation
    
    
    :example: response = client.update_shard_count(
        StreamName='string',
        TargetShardCount=123,
        ScalingType='UNIFORM_SCALING'
    )
    
    
    :type StreamName: string
    :param StreamName: [REQUIRED]
            The name of the stream.
            

    :type TargetShardCount: integer
    :param TargetShardCount: [REQUIRED]
            The new number of shards.
            

    :type ScalingType: string
    :param ScalingType: [REQUIRED]
            The scaling type. Uniform scaling creates shards of equal size.
            

    :rtype: dict
    :return: {
        'StreamName': 'string',
        'CurrentShardCount': 123,
        'TargetShardCount': 123
    }
    
    
    """
    pass
